OPJ
Established Member
Simon, I bought a book a few years ago, titled something like "Guide to Home Improvement Costs". It covers most second-fix building work and gives the home-owner a rough idea of what they should be expecting to pay for certain jobs... I've never had to use it myself but, it could give you some ideas? This was maybe four years ago so, there could be a revised edition by now. Might be worth a look.