Prompted by last week's AP, I claim a
Wrayflex 1, one of about 850 built.
Your one and only British SLR, complete with 24x32mm frame size so you had to mount your own Kodachromes, and a mirror instead of a pentaprism so everything was left/right reversed in the viewfinder (or upside down in portrait).
Traded for a Nikomat some time around 1970