As per SeanM1997 on twitter,
Loganair to reduce Teesside base from 2 to 1 aircraft from 25 May
Southampton and London Heathrow to end on 24
Will continue to operate Aberdeen, Belfast City, Dublin and Newquay.
From personal point of view very unsurprising loads for a long time have been nowhere near good enough to sustain Heathrow especially due to rising costs. Wouldn't be surprised if some of those remaining ones don't return next summer ie Dublin and even Newquay