if it was a surestop stopcock then thats different. they are a valve that works on pressure meaning the water supply can be shut off via a switch similar to a lightswitch. they are very convenient and reliable. They are also more expensive and takes more work to fit than simply fitting or replacing a standard stop ****.
160 may seem steep but the moral of the story is to get a quote first. For a job like this the plumber should have given the quote anyway in my opininon
On the other hand, no one here as seen the job and so doesn't know for sure what was involved and exactly what materials were needed.
maybe next time try - Pete Green & Sons Plumbing 01709 374546 or 07748 483761. price always given beforehand, the work involved explained and work guaranteed