Transiting through Heathrow with PIA

[muradmohsin]

Anyone recently transited through Heathrow after getting off PK757? My friend just bought a ticket using BookMe and it is under one AirFrance PNR (flights operated by delta). The itinerary is LHE-LHR-ATL-MDW. After a bit PIA sent their own booking confirmation via email with a separate PNR?? It’s got us pretty confused about whether he will need to checkin again at LHR or whether he can stay airside and his bags will be sent through. I looked online and there’s no information at all. I know that AF and PIA have a codeshare agreement when going through CDG but I’m not sure about LHR. Some clarification would be great. Tried to call PIA but none of their numbers in the UK seem to work for some reason and their WhatsApp seems to be dead too unfortunately. Thanks!