that sounds a little on the dear side mate if its already wired up,i would say there £150-£200 + vat in materials there,if i was estimating for the job (would personally have a code also instead of a fob)

on average i usually take a day and half to wire up,install & commission

so they have about 4-5 work to do and get £320

nice little earner

but then i dont know what labour costs are like where you

D.