Where was Abbas Hilmi mess?

I’ve been sent a photograph of an ashtray made out of an aircraft piston that has ‘ABBAS HILMI MESS’ engraved into it and wondered where this RAF (or RN?) mess actually was?

Presumably ‘ABBAS HILMI’ refers to Abbas II Helmy Bey, also known as Abbas Hilmi Pasha, who was (apparently) the last Khedive (Ottoman viceroy) of Egypt and Sudan so maybe there is a connection with Egypt or Sudan?

I’m going to get a look at the ashtray soon but I’m pretty certain that it is (very ‘professionally’) made from either a Bristol Pegasus or a Bristol Mercury piston.