There's also a register for Swallow-bodied cars of all types (mostly populated, from memory, by Austin 7 owners which is my erstwhile and tenuous connection, but apparently it has since expanded to include other marques). www.swallowregister.org

If it's a peculiarity of the Swallow coachwork rather than the Wolseley chassis, there may be someone there who can help.

Doug
1985 4/4 4str, Jubilee Blue