Questions about IFISA

The P2P part of the law might override that, I haven't reviewed it again to check, but even if it doesn't, the guidance explains how HMRC expects to act and how HMRC interprets things and HMRC does have some discretion, as we have seen in its treatment of deduction of tax from interest on P2P payments.

On many platforms it's impossible at present to put part of a loan up for sale and then buy only a different part of the loan so you're not buying back from yourself. On some it is possible. Given the broad actual inability to not buy back from yourself without restraining from buying back at all it seems like at least a sensible use of discretion by HMRC.

So long as there is not any sign of widespread pricing abuse I doubt that HMRC actually cares much about these specific rules, which seem to be purely an anti-abuse mechanism.

Of course, with many platforms anticipating going through the FCA processes to become ISA managers as well as to become fully approved for P2P we may end up with some further practical guidance based on how the platforms actually implement things, since I assume that the FCA would not want to approve processes that are illegal.