Hi MME4eva:
In regarding LBA-LHR Route bmi regional's Embrear aircraft only operate the following LBA-Heathrow flights
BD421/BD422 Monday, Wednesdays, Fridays & Sundays
BD411/412/413 Saturday & Sundays
BD418 Sundays
BD420 Saturdays
All other weekday and weekend sectors are operated with Airbus A319 or the A320's