Be very careful when looking at costs for resprays. You get what you pay for. Look at their previous work, what is their reputation like locally. Most of the cost is in the preparation work, which is often skimped on and doesnt show up until about two months afterwards. There is also a lot of difference in quality of thinners and primers used.
I would say that £1600 including stripping and refitting, and painting ALL exposed metalwork is far too cheap for a pukka job.