The idea of the waiver was more a signature to make sure the customer is aware that they're responsible and they've signed a bit of paper to say they not going to break the law.
No legal standing at all, but if the idea behind AT was to try to stop numpties buying an airgun and winding the power up, they might think twice if they've got to sign a bit of paper. (probably not though)
The really stupid situation we have now though is that if you want to bypass all the AT nonsense and the VCR act, you can go online and order a new gun from Europe and have it delivered to your door, and save yourself some money in the process too.
Where's the logic in that?
I'd be nervous about a change in law. You open up discussion about changing the law on airguns in parliament and there's a very good chance that it won't go the way we want it to.