hi paddy
the quick answer is it can be done and isnt hard… about a 3 layer vinyl job would cover it… maybe the odd highlight here and there too..
what you need to do now, (knowing you have only opened doors) is get back to him and tell him no problem!
give him a price for cut vinyl and one for printed. an edge will this no sweat.. adrian at signrite has one and will probably give you a good quote no probs.. try calling him and ask for a quote.. get back to the guy and give him quote (A) vinyl quote (B) printed full colour…
get the ball rolling mate.. if he says yeh to eather get a deposit for the proof you give him. this will cover for the printing at least.. till you get paid in full…