Roy,
Has anyone applied for his records?
See here:
Service records
If you are not Next of kin, you will need to get consent from whomever it is to apply, or the NOK could apply themselves. Bit of a wait, but worth it according to those who have done so successfully.
War diaries, available at Kew but not online, is also another possiblility for finding out what his unit was doing around the time of his death. Unlikely to mention him though, as ORs are rarely named.
Good luck with research,
Diane