LM cancelled 11 sectors to or from LCY In the 9 months between the beginning of May last year and the end of last month. That was a huge improvement on when T3 operated the route.
However passenger numbers on the route have steadily been declining over the last couple of years. They were down 8.8% this year on 2018. The average load factor was less than 65% across the year. The current arrangement with LM works for BACF for now, If this was to end then I think you might have a chance of seeing BACF operate a E70, however I very much doubt they would base the aircraft at IOM. Instead they would fly a morning and evening flight on weekdays with the aircraft being based at LCY.