Originally Posted by spotwelder
You might be able to out and back check-in. I will check if there is a transfer area without needing a visa etc in a couple of weeks.
I have never been able to get boarding passes in LHR for the return. There is a transit desk. No visa fee necessary if you stay in transit. I have been able to make the turnaround from the morning flight to IST to the afternoon return to LHR.