I'm only working on what's in the DM but the claim is the Ambassador invited World Health Organisation officials to the British Ambassador’s residence for Ifta....
Embassies/Ambassadors do that sort of thing or similar on a routine basis for various groups.
Question is did the Ambassador know ahead of time that H&M were going to tag along...
If the Ambassador did know ahead of time what would have been repercutions if he had said "no...."
If he only found out when they arrived, again, what would the repercutions have been if Ambassador and/or staff said "you two - no entry".
I suspect the diplomatic thing to do from the Ambassadors POV would be to politely ignore as much as possible but maybe report to London.
...and if H&M had any sense of tact and diplomacy just maybe they would have realised it was not an event to attend, because just them being there would create waves......
As it is the Ambassador has been dropped in the brown stuff.