I suppose my usual routing is gla-dub (but aer lingus); then dub-lhr-mia-gcm-mia (aa) - lhr - dub then aer lingus to glasgow. So i guess it is 50/50 for me for ba only being dub-lhr-dub connections to lhr-mia-lhr. I never need (want) to go to london so no gla-lhr for me; and with living in caymn for nearly a decade i have no desire to go somewhere warm on holiday.