A few thoughts provoked by comments already posted by others on this accident:
Was this aircraft carrying out an ILS or any other type of IFR letdown? Does instrument flying training/recency therefore have something to do with this accident? I must have missed an initial report...
I think basic mission planning / contingency planning is perhaps one thing the AAIB might be looking at closely, as well as other things, in this case.
I first flew SPIFR in 1979 and have done so for much of my career since, although I have quite a lot of multi-crew IFR time too. More recently I flew a 109 SPIFR for some years before the owner decided he might like someone else to have a chance of landing it if I popped my clogs in flight.
Medical grounds only was the rationale behind the decision; perhaps he thought I looked a bit peaky...
However, the CAA do not mandate two pilot ops for our type of operations.