TR6 factory hardtop will fit the 4A and 250. Surrey top is period correct for the 4A and 250. Surrey will fit the TR6 as well. I think one or two of our members have one on their TR6. I have a couple of the Parrish aftermarket period correct hardtops for 4As like on the green one in Piggotts book, if any one wants one.
Marv