In that case, there should be architect’s plans available; you might have to go to your local planning department’s archives to get a copy. (The owner/operator should have a (kept up to date) set of the plans, but that’s usually just wishful thinking.)
That’s all a quantity surveyer needs to prepare a tendering procedure.
Stuff like that was part of my job for the last 20 years or so. If you send me the data, I can quote you an estimate for my fee, which will be subject to the terms and conditions of the HOAI.
