smartrs

i know lots of people take stuff like a underside restoration and genrally making the underside look nice and clean ish but is there companys that take this kind of work on or isit a case of chatting to local garages and explainging to them what you want to achive as in compleatly strip the underside make good any holes or rust cover all with a nice finish and re-assemble the underside .

i know mine needs work doing at some point soon as the spare wheel tub as rusted through and the sills are showing signs of rust the rear beam mounts have already been done a few years back for a mot by a rs garage local ish to me but it does not strike me as a job for them to do a whole cosmetic re-furb or is it a job for a body shop ? i would give it ago my self but i have limited time and skills and space to do it .
rougly how much would the underside of a saph be to do or does it end up cheaper to re-sell ?

sorry for so many questions
Paul