Art Deco wrote:
Can these be painted like any other kind of wooden door?

Er... yes, why ever not?

I'm wondering if it's worth it, given a new one can be bought for £15
or so.

Are you talking about the hollow MDF type, that are white when supplied?
They are provided pre-primed, that's all: you still have to paint
them with undercoat and top coat just like any other door or painting job.

David