WANTED: 12 Inch Four Stud Wheel (Seaham SR7)

WANTED
12 Inch Four Stud Wheel
Seaham SR7
DESCRIPTION
These are about as common as hen's teeth these days but I'm hoping someone somewhere can help me out. I'm told that wheels from an old Austin *** are the same as the type I'm looking for, to use as a spare for my trailer. It should be a four stud wheel with the hole centre's measuring 4 and a half inches or 114 mm across the diagonal. Any help would be greatly appreciated and I can collect at your convenience. Many thanks.