Iphone 4S smashed front and back

don't believe apple offer such repairs but other shops does

the price would very much depend on where one is in the world

when you say gbp then one would assume uk

I'm not sure about the prices there but where i'm at in Denmark

for compare I'd have to pay 159 gbp to have my broken ipad screen fixed

I just had my front glass replaced and it was $120 US. A lot of different places offer repairs and replacements, just do a google search.