You will notice in the photo evidence that these come with the comics and were thus not initially meant for UK distribution. Instead, these are grey imports, which means they weren't brough over by Hasbro UK but by another importer.
It's similar to how BBTS imports platinum editions from China and sells them for a similar price to the exclusive US retailer. It is also called parallel importing.
The fan who gathered all this news for us, TFW2005 member Payres, explains it better in the following quote:
A "grey import" is a toy that's been imported into the UK by a firm other than Hasbro themselves.
This usually means there's a sticker somewhere on the packaging saying "imported by" and naming the firm.
This particular firm has a record for this sort of thing going back to the mid 90s, maybe earlier
Grey Imports are frequently left over stock from another region so the boxes/cards for the toys are usually not the standard ones for the UK. Sometimes it's hard to tell but there's a dead giveaway here as these CW toys have the comics which the UK versions didn't. Last year lots of chains got cases of T30 Voyagers in stock, which we never got here.
Generally grey imports are sold to discount chains such as TK Maxx, Home Bargains and B&M. The discount chain mentioned here is a new one on most people. However at this time of year, when shelf turnover is high, they can end up in normal retail stores.
How widespread it is outside the UK I haven't a clue!