You probably know this already but Air-Britain gives:
V5526 608 Sqn Engine cut on convoy escort; ditched 8m E of Tynemouth, Northumberland, 17.04.41.
That would have come from the Form 78 Aircraft Record Card.
I would suggest that your starting point would be the 608 Squadron ORB (Operations Record Book) held at the Public Record Office at Kew.