Waste of money?
I could understand the price if we were possibly talking about his original hand-written drafts, but these are just offprints - i.e. published works probably available in thousands of copies in libraries world-wide. Why waste money on buying those - there's nothing special about them - just visit the Bodleian or BL and get a set of photocopies for about £20.
If they've got that sorrt of dosh to spare how about spending it on repairs to Bletchley Park itself - or the Enigma machine (if they haven't already got one)