Enough is probably the answer. Frame head is about £70 to start with, and it needs to be bob on straight. I'd also expect that they'd probably only want the chassis to do the work. That way you can reduce the cost, but I still imagine the labour could be pricey.

 

Ive done a few, labour and barts normally come in at 4 - 500 quid. be warned you will probably end up needing the chassis surport pannel as well, they seem to rot out at the same time as the frame head!
You will get charged more from some one who hasnt done one before as they will take half a day to make a jig up

 

i've a brand new framehead which i was going to use on a buggy chassis but i've no time

£50 in bristol or i can get it to brum anygood ???

will save a few £££