As said,just get the parts for now,but just put the belt on, take the plugs out and move it by hand,do not start and run it cos if it is damaged it could jam and snap the new belt anyway,so by hand to be safe.If all moves ok,replace the parts,but that does not indicate everythings fine.At the end of the day it is better all round to just whip the head off,should take no more than an hour if taken ye time.Dont for get the inlet and outlet will need removing.A new head gasket and bolts for futures sake will help anyway.Unless you had gasket probs u dont need a head skim,and whilst its off u might as well give it a de-coke if alls ok.Buy a haynes manual cos u will feel great afterwards that u did it yourself,and save a hell of a lot of money.Even if the head needs replacing,look for a second hand one IN GOOD CONDITION,and learn to do the work yourself.Tbh,its how mechanics done it when they where learning,they have to read and do the prectical work themselves,so why not you??