I think you're over-engineering the problem, all you need is a spycam.
Treating employment as a business transaction carries the risk of allowing market forces to transform the working population into a horde of soulless, placid automatons.
Why's that scary? The HFEA is a british goverment agency that issues licences to carry out research in this area, to prevent rogue scientists carrying out experiments that might harm any babies born as a result. It's pretty liberal as well, at least far more liberal than its US equivalent without being reckless.