I'm sorry, but you are wrong about sound moderators not having to be sold face-to-face by an RFD or via RFD transfer. Existing law absolutely requires sound moderators to be sold through the RFD process. And why on earth wouldn't they, given they go on slots on FAC like other S1 component parts and accessories? Please get this error amended ASAP, before you discuss anything further with the UK Government. Getting a slot for a mod is a doddle. Always has been. I've got more slots for them than I need. The issues has always been not being able to buy them online and having to pay ridiculous RFD transfer fees, unless your local RFD stocks them.
As an aside, I also know more than a few RFDs who do not agree with your claim that S2 sound moderators are already exempt from licensing. S2 shotguns are still firearms and still subject to the definition of a firearm, but they are a subgroup with a specific definition to do with barrel length, magazine capacity etc. The argument I have heard made by those more knowledgeable than me is that there's nothing that explicitly says shotgun moderators fall outwith licensing at present or that says the sound mod subsection of the definition of a firearm doesn't apply to firearms that are shotguns, thus they are still subject to the RFD process above, if nothing else. I'm not a lawyer, so I don't know precisely, but there's enough doubt here that I think BASC needs to show its legal advice on this matter so we don't ended up with flawed legislation.