Just a theory, but maybe this year has been so bad because of the poor winter/spring weather. At the first sign of decent weather in the last month or so, pilots set off.
1. They are rusty
2. their aircraft have not been used much for months.
Both pilots and aircraft perform better if in regular practice.
This does not of course explain the sudden rush of airshow calamities, where one presumes the pilots have been in as regular practice as normal.
I don't think that aviating in the UK has suddenly got inherently more dangerous.