Of the three 'Wall's' Chris mentioned, all were 1944 deaths, so if all those details you have Finn are accurate, it counts them out. As mentioned, looking at RAF, RAAF and RCAF, I could find nothing on any 'Wall', or anything close that started with 'Wall'.
I have to point out, that for an identification to be recognised by the Commonwealth War Graves Commission, the name and service number on the clothing almost certainly would not be enough. Although probably not usual in the case of underwear, there would always be the possibility that an airman might use a mates clothing, scarf, spare socks etc. As a result, finding such a number alone would not be taken as proof of the identity of the body.