Absolute non-starter.
BA have better things to do with their aircraft.
They currently offer daily connections via LHR and though it involves a transit from T5 to T3 on the outbound this is done airside via Flight Connections so there is minimal Heathrow hassle.
Also as BA common rate their fares ex Scottish airports there is no real penalty for using the LHR transit.
VS pulled out of GLA-LAS so now Thos Cook have the direct market sown up.