the Air Historical Branch of the RAF has concluded that Ballard meets the criteria to be awarded the Battle of Britain Clasp to the 1939-45 Star. Any surviving family members could claim this on his behalf.
I wonder if stocks of the original "Battle of Britain" clasps are still held by the MOD Medal Office. I somehow doubt it, and if his surviving next of kin is traced and they put in a claim for the clasp then I hope the clasp they receive will be identical to the originals. The medal office does not have a good record in this respect. When the "Canal Zone" clasp was authorised for the old General Service Medal some years ago, the lettering on the clasps was noticeably larger than that on other clasps on these medals, and the error was quite obvious on multi clasp medals.