Quite a few times. Mainly because the weather has dropped below minima.
I fly around London a lot Fog at Southend usually means you get into Biggin which is high up. Biggin which is high up usually gets low cloud which means a diversion onto the Ils at Farnborough or Southend.
Strong headwinds a couple of times for fuel concerns.
Mechanical problems a few times too.
Passengers changing plans mid air a few times too
Ill passenger twice
Pace