From memory Maersk did serve Oslo from BHX
Just picking up on OP's idea, could they serve a Scandinavian point on a w pattern from say one of the Scottish points or Newcastle.
What's the effective range of a E145 with full pax and luggage. Wiki gives a fig of 1550 NM for the 145LR variant but not the corresponding payload and BMIR may be operating a different variant.
BHX-HEL is approx 1150 NM (Slightly unrealistic I suspect - A statistical problem I know)) from
Great Circle Mapper (and Oslo approx 730 NM)
CAT III