Simon Glancey has submitted the following:
Sgt Wallace was killed in Short Stirling III EH924 QS-B of 620 Sqn, R.A.F., which crashed near Asperden, north west Germany, on a mission to bomb Essen on July 26th 1943. Of the seven crew, only the rear gunner survived.
Bomber Command Losses 1943, W. R. Chorley, 2007, Midland Counties Publishing, ISBN 978-1904597905, page 244.
He is remembered in Alnwick on A11.01