Get someone to inspect and mark an original Land Reg. map.
Ring your local Architectural Technicians. (or Building Surveyor's)
Get at least 3 written quotes, from experienced professioal with full PI insurance.
Ask each to quote to mark a site off a Land Registry map - circa €150 + VAT for a straight forward one.
You must use an Original Land Registry Map - photocopies are not acceptable. It must be marked to Land Registry rules (very simple rules - outline site in red, state area in metric) and contain a signed declaration, which is also dated.
Your Solicitor should know this?
Its either right or wrong, black or white - the Land Registry don't do "grey"