FWIW
This looks like a DH Chipmunk as used a while back
by University Air Squadrons in the UK and quite
possibly before that as RAF initial trainers but I am not sure.
Marking certainly look right for UAS machine but
I think that some still flying in civilian use are still painted
to look the part.

Pilot must have got a shock too.
Little black blob travelling straight down at 150mph turns
suddenly into floating thing very close by. Maybe though
the 'chutist was behind the pilot when the 'chute
opened?

The aeroplane is in the shot for about 4 secs before the
close encounter.