hey Mark, a few months ago i picked uo an hp psc 1355 all-in-one jobby (sweeeeeeeet machine) for my biz as well. printer/scanner/photocopier(b&w and color), it is great.
bought it here in madrid at "pc city" (called "pc world" in uk) on sale for 100� but the nornal price is 140� (i think).
instructions were in english, spanish, etc... and i am pretty sure the warranty is europe-wide so hope that helps to answer your questions.
also, all you would need to use it in uk is a 2� plastic adaptor to get it into the uk socket.
they had other makes and models that cost as much as 400�
as for your model (or close),
CARREFOUR lists the epson stylus cx3650 multifunction for 135� so i guess prices on these things are just as good here in spain if you know where to shop. click
HERE for that page at carrefour.
actually, you got it backwards, normally electronics are cheaper in uk than in spain but the uk is still not the consumer electronics haven that is the u.s.a. just see the page
HERE for superior models at $108 u.s.d.

although who wants to have to use a transformer with their printer.
on a side note, this x-mas my mom came to visit and i ordered a new laptop from sony.com and had it sent to her so she could bring it to me here in madrid. now there was a huge savings. it cost 1,700� less via sony.com who only ships to u.s.a. than it would have if i bought it from sony spain or a sony dealer here.
i guess the decision on where to buy would come down to what item it is, how much one would save and where (in which country) one would be using it most.
for my laptop i did not think twice before buying it via u.s.a.
mom also brought me an ipod 60gb photo for a friend which was approx. 450� on amazon.com and the cheapest place here had it for 630�.
saludos,
jer...