37mm Bofors

[Mobhack]

Looking at the wiki article on the thing

A number of Swedish m/34 ordered by Anglo-Egyptian Sudan were adopted as Ordnance QF 37 mm Mk I.

so probably not a lot of those in UK service at all. Usually seen as a portee mount, attributed to the LRDG rather than as towed AT used by the regular forces. I bet Sudan would have bought maybe 24 items or even less.