Another thing to keep in mind with the UK and London specifically is they got quite a few international airports. Supposing you don’t mind “settling” for a less known airport like Gatwick or Manchester instead of the obvious Heathrow might yield additional results. For instance, Emirates flies to Gatwick (LGW) and Stanstead (STN) in addition to Heathrow (LHR). They also fly to Birmingham (BHX), Manchester (MAN), Newcastle (NCL), Glasgow (GLA) and Edinburgh (EDI). Qatar flies to similar destinations in the UK.
And look there might be some advantages here too. For instance it may be closer to your final destination in the UK. And immigration and security may not be as much of a mess as LHR can be at times. Certainly for my money I’d fly into LuCY (aka London City Airport) so I don’t have to deal with the bs of getting into London.
-RooFlyer88