Lloyds Club account is £120 a year with annual travel insurance (and lots of other things), covers cycling but not cycle racing, which either does or doesn't exclude PBP depending how you squint at it
I have HSBC Premier which likewise excludes racing...
EDIT to add: I now notice HSBC exclude all all "training for, or taking part in any race or time trial, organised sports event or competition" so fairly useless.
I see Post Office doesn't mention racing but exclude Cycle Touring, which would be a warning flag for me.
End of the day, so long as I have 3rd party liability cover, I'm comfortable self insuring for anything else same as I do on any UK bike ride.