Agree with SASless, I had an engine failure at 700' in an AB206A, afterwards I was asked to complete a report that asked for N1, EGT, oil Px and Temp etc. at time of failure! Sorry, wasn't looking, no idea, I may have seen something but all mental ability was directed to getting down safely. Sounds like this accident was a whole different ball game, possible control failure at 400' in poor viz, I wouldn't expect the pilots to remember much at all.
I would have hoped that the Royal Navy still had a helicopter with a sonar buoy that they could dunk near the accident site that would pick up the FDR.