For my FR+ I got the water pump off eBay for £23 delivered - no surcharge for an exchange unit.
I got my cambelt kit with tensioners etc for £83 inc vat from The Parts Specialist (TPS) in Teesside.
Also, auxillary belt - £15 from a local motor factor.
SEAT and other technicians recommend that you change waterpump and auxillary belt when you do the cambelt as removing the old one can unsettle the waterpump etc and cause problems a couple of thousand miles down the road. For the sake of a few quid it is worth doing.