Thanks Tom.
I shall certainly give the carpet a good wash.
It has been an issue from day one of receipt of the refurb'ed boat from RS. And I believe from various sources that there was a batch or more of overly think dagger boards.No replacement forthcoming despite request.
There is a noticeable increase in profile thickness at the heel of the board, which is where it appears to stick.
Anyway, I've done some sanding, and cutting to get back to smooth and hopefully this will help.