It is my opinion that if print stability/longevity and "gallery-worthiness" is an issue for you, then you shouldn't be thinking about using RC papers anyway - you should be working on a quality fiber base paper.
The problem as far as my searches go, is that in the U.K. Foma paper appears to lack the competitive edge that its film has in comparison with Ilford. It has never been clear why this should be the case.
If anyone in the U.K. knows of sources disproving this then let us know.
I always wonder about Foma prices. The sheet film seems to be a particular "bargain" assuming quality control is acceptable. As you say UK prices on Foma paper can be oddly high. UK sourced '120' roll film from ILFORD is about the same price as Foma, whereas on the continent the Foma product is priced as a budget option - see fotoimpex.com.
I use Fomaspeed MG 313 Velvet RC for contact sheets and I like it. I find it similar to Ilford MG Pearl RC.
I dont think that there is significant difference in the end, I would buy Foma paper, but I use RC only for contact proofs.
Foma has its own web shop for their photographic products, and for whatever reason they undercut regular retailers by a wide margin. It appears, that both Foma and Ilford provide their products to some outlets without middle men, thereby omitting hefty markups.
Bonk, I'd like to endorse this sentiment. If you are in the U.K. or even mainland Europe then Ag-Photographic is well worth a look as a source of all sorts of analogue materials. Not the cheapest on everything but then again no one retailer ever is