I agree. That's where I thought an Inglis Hi Power might have come from. Would make sense if airdropped with Stens.
Not sure if the OSS or SOE would have access to Belgium Hi Powers after the German invasion. But the British Purchasing Commission bought Argentinian HAFDASA Ballester-Molina .45's to airdrop to partisans. Probably the same with the Spanish Star and Colts.
And the Brits would most certainly be able to get the Inglis copy from Canada. Not completely sure, but I believe the rear ramp sight pistols were Chinese contract pistols and may not have been all delivered.
Any chance of getting the serial number?