I've read the relevant section of the bill and it is quite frankly a load of half-a**ed BS.
Folks in the Lazer-Tag community (who have been in touch with them) say the police don't like the incoming legislation at all, and will most likely ignore it if they can. As far as they are concerned, the illegal firearms act thingamy already covers everything relating to a**holes strolling down the high street with toy guns stuffed down their pants. They literally have not got the time for it. It will likely come down to some future test case if ever one comes along.
However it remains to be seen what happens with ebay.uk itself, If some "kids n' guns" parents group kick up a stink they may feel pressured to do something like ban the sale of gun shaped lumps of resin and alloy. By that point we are getting into banning the sale of toy guns in toy shops territory, which is so far past the Political Correctness Gone Mad(tm) stage, it stops being funny anymore.