Not this old chestnut again
NO bullets have to be entered on your FAC by "LAW", regardless of whether they are expanding or not. Anyone who tells you they do, be it an RFD or a FLO, is wrong. Ask them to point you to the section of the Firearms Act, or Home Office Guidance document, where it says they do.
"Some" constabularies now "request" that RFD's enter expanding ammunition on your FAC. This is not law and is, to all intents and purposes, illegal as only ammunition and firearms can be entered on your FAC. A cynic would say this is back-door law making, others would say certain RFD's have made "accounting errors" in the past and the powers that be are trying to wind them in. Either way, expanding bullets don't go on an FAC.
Expanding bullets are to "be regarded as ammunition" only in the sense that you have to have authority to buy them in the first place and they count toward your ammunition allowances.
If your RFD insists on entering expanding bullets on your FAC, I would suggest you stop using him and go to someone else. I have been buying expanding bullets for over 25yrs (way before they were restricted in any way) and have NEVER had them entered on my FAC despite buying a few thousand a year.
MidwayUK, or any other supplier, can not send you expanding bullets directly and have to send them via an RFD. This is simply because they can not verify your FAC conditions without you being there in person, FAC in hand.
As far as I am aware, it is not illegal for the USA to send expanding bullets to anyone in the UK, but it is an offence for you to receive them
. This could have changed tho, depending on the sellers interpretation of the Patriot Act brought in a few years ago.
There is no problem with them sending anyone non-expanding bullets, or you receiving them. In fact, I import a couple of thousand a year myself