Experience
Practical experience across a range of complimentary sectors.
Calum Gillhespy’s career began as a rural practice surveyor with later specialisms in the development and energy sectors. He was amongst the first cohort of RICS trained mediators and now sits on the RICS arbitration and expert witness panels.
This experience now informs Wyldmark’s approach: clear, commercially grounded and focused on helping clients move complex matters towards practical outcomes.
Experience shaped by real matters.
Wyldmark is built on practical experience, not abstract advice.
Calum’s work has involved combining commercial judgement with a detailed understanding of the projects he is involved with. Knowing how matters work in practice, how negotiations unfold and how evidence can support better decisions is combined with a positivity which consistently delivers a results orientated approach for clients.
Read the ground. Define the route. Move forward with confidence.
Wyldmark’s main areas of work
Strategic site promotion
Long-term involvement in identifying development potential, coordinating technical input, engaging with planning processes and supporting sites through promotion and delivery.
Development agreements
Experience negotiating and supporting option & promotion agreements, sale contracts, landowner agreements and addressing contentious landlord and tenant matters.
Purchase price negotiation
Evidence-led negotiations to agree purchase prices, appraisal testing, cost reviews, gross development value analysis and pursuing an agreed negotiation strategy.
Dispute avoidance and resolution
Sitting as an arbitrator determining farm rents and notices to quit, advocacy and expert evidence in land value tribunals, expert witness reports and mediation of rural disputes.
Examples of Calum’s recent experience.
Landowner led site promotion
Context
A long-term residential-led development opportunity, beginning with identifying the site’s potential, forming the strategic vision and delivery strategy, site promotion, technical team coordination and phased disposals.
Role
Calum’s work included masterplanning with an architect and technical team, overseeing site investigation works, acquiring third-party rights, coordinating local plan representations and negotiating phased sales.
Outcome
The work supported three successful planning applications, sales of 640+ units and pre-application advice for a final phase including 1,200 homes, commercial development and a community hub.
Promotion agreement - new settlement
Context
A promotion agreement for a c.5,000 home new settlement involving multiple development partners and an element of retained land within the development for the owner’s own use.
Role
Calum negotiated the promotion agreement, supported engagement with protected tenants and helped secure transaction approvals, including a Charities Act report and presentations to the Trustees.
Outcome
Ongoing engagement with development partners and stakeholders through the local plan process, input into the Vision for the development and early engagement with tenants to secure the most appropriate means of site delivery.
Option agreement - affordable housing scheme
Role
Calum advised on development potential, obtained pre-application advice, took the site to market with detailed heads of terms, supported the legal process and worked collaboratively to add and preserve value.
Context
A 200+ unit affordable housing scheme following a review of potential development sites across a client’s estate and conducting workshops to articulate a vision which encapsulates their wider ESG objectives.
Outcome
The deal was documented in three months, with hands-on engagement used to overcome site constraints and maximise development potential, engaging constructively with the buyer of the site.
Land value negotiation
Role
Calum led an evidence-led negotiation, engaging a technical team, reviewing costs, testing the appraisal and procuring an external peer review.
Context
A 400+ home development under an option agreement, where the price notice was served at the minimum price in the contract.
Outcome
The 12-month negotiation achieved a 50%, multi-million-pound increase in the purchase price.
Arbitration advocacy - development site purchase price
Context
A purchase price negotiation and arbitration relating to a 200+ home site under an option agreement.
Role
The matter involved collating evidence of tendered costs, gross development value assessment and leading a multi-disciplinary team in the commercial negotiation and subsequent advocacy.
Outcome
Calum’s role was one of advocate and included proactive and flexible engagement with the arbitration process, adapting the strategy as the matter evolved and explaining the process to lay clients.
Expert witness report - deferred consideration
Context
A potential professional negligence claim relating to deferred consideration following a development site sale.
Role
Calum prepared expert evidence considering the seller’s loss, reviewing a complex land transaction and Section 106 agreement across multiple landowners and strategic-scale infrastructure delivery.
Outcome
The work assessed the market value of the land relative to the consideration received and informed the client’s decision whether to pursue their action.
Arbitration - farm rent review
Context
A documents-only review of rent on a Yorkshire Wolds farm, referred through the RICS Simplified Arbitration Service.
Role
Calum carried out an unaccompanied farm inspection and reviewed the matter through the Simplified Arbitration Service.
Outcome
The award was issued within three months of appointment, showcasing the ability of providing a focused, efficient dispute resolution service.
Expert witness report - development site marketing
Context
A dispute between owners of a shared equity site regarding the best way to conduct it’s sale.
Role
Calum acted as a Single Joint Expert, carrying out a site inspection, local market review and assessment of key constraints to produce a court compliant report.
Outcome
The expert report considered the effect on land value of addressing constraints before marketing, compared with leaving them to the buyer.
Arbitration - Agricultural Holdings Act tenancy
Context
An arbitration relating to an Agricultural Holdings Act tenancy where the landlord had served a Case D notice to quit.
Role
The matter involved a preliminary issue around the interpretation of a manuscript change to the lease, with evidence relating to the conduct of the parties across a 40-year tenancy presented at a hearing.
Outcome
The arbitration involved multiple awards, conduct of a hearing and determination of liabilities for costs linked to the effect of a Calderbank offer.
Where development experience and dispute resolution meet.
Many matters do not sit neatly in one category.
A development agreement can become contested. A valuation issue can shape a wider negotiation. A dispute may require practical understanding of how residential-led sites are promoted, appraised, delivered and sold.
This is where Calum’s experience is particularly relevant. His background allows Wyldmark to bring development understanding into dispute resolution, and dispute awareness into development consultancy.
The result is advice that stays close to the commercial reality of the matter.