In reply to Infinite Granite:
Plastic pipes are pretty standard for most parts of a central heating system these days.
I am however mystified by the copper pipe running horizontally inside the boxing. It seems unlikely that both that and the plastic are connected to the radiator...
If it was done well you might expect to see the hole in the wall where the pipes emerge sealed with a neat little box so you don't have air flow between the wall and the room?
Edit: As I understand it you can now get side (rear) entry radiator valves that allow the plastic pipe to enter the radiator from behind effectively unseen, meaning that unsightly boxing and "pretty" stubs of copper can be done away with entirely.
Post edited at 22:33