PN:
"Selling off a couple of frigates at eBay prices would probably not even pay for one FFC or whatever."
I agree. I was thinking more that the package might involve trimming two or three of the planned T26s from the current planning assumption of 13 and replacing them with a larger number of low end vessels (largely cost and manpower neutral) to achieve what could then be portrayed as an increase in hull numbers overall.
There does seem to be a realisation that hull numbers is an issue. I guess it's also possible that the funds could be found from savings elsewhere, as the RN isn't exactly over-endowed with escorts now - it depends how "rebalancing" is interpreted in practice.