I stumbled across this while browsing today.
https://ibccdigitalarchive.lincoln.a...document/25665
It's a pdf document of the Pilot's flying log book for George Alexander Mackie, covering the period from 24 September 1943 to 17 February 1946.
He flew with 214 squadron based at Chedburgh in Suffolk at the time and was on the same mission as the EH880 crew. On pages 8 and 9, there are details of the mission they undertook on the 1 December. It mentions them 'gardening' (RAF term for mine laying) in the Baltic off a place called Laeso (part of an island off the South East coast of Denmark). At 15.20 they were diverted to Acklington.
Page 9 has a newspaper article cut out about the crash.