Are they allowed? Consumer protection laws in the UK suggest that up to a year after purchase one may be able to get a full refund or a fixed product at the customers choosing ... not sure why/if that differs for some reason with digital products.

I'd guess most copies are bought by businesses whom such laws don't aid.

It probably isn't difficult to get around such laws in light of the fact that you're actually purchasing a license to use the software and not in fact buying the software. The license-purchase paradigm usually means the vendor can do whatever they please, up to and including pulling the software right off your machine should they feel like it. Examples of the aforementioned include the kindle book scandal and sony pulling games out of their online marketplace that people had already paid for.