The situation is now worse...
This item can be found on Ebay using the item number 290606344730.
Now I have had the time to have a go at it I have found that it is held together by 3 tiny screws, the holes for them are quite visible, which are not supplied, and one is hidden under a decal (an Opel one mind you) that has to be stuck on after reassembly

so I emailed the seller and his response was 'I have sold many of these and they just snap together but if it needs screws you can get them from any hardware store'. If no screws are used it will not stay together and every time you flip the lock to expose the blade the thing falls in two! Some frikking help that was but anyway I tried all of the ones in Leicester and none sell them so tiny - they are in fact a specialist component and have to be ordered from a specialist electronics supplier. Add to that they can only be ordered in bulk packs and it makes me feel I have been ripped off by a seller who does not examine his goods before sale. Surely I could expect that it came with the screws needed?
My advice has to be do not buy the flip key off Ebay even though it is off a decent quality. At £13.99 it would not have broken him to have supplied 3 tiny screws! It is a pity that the aftersales service is not as good as the item quality. My feedback to the Ebay seller will therefore been a very negative one unless he comes up with the screws needed. :-/