Priority pass works as advertised.
Haven't used any of them in London. The 6 in London Heathrow would be as follows:
1.
Airport LONDON,Heathrow
Lounge TRAVELEX BUSINESS CENTRE, HEATHROW
Location Landside - the Lounge is located in the Queens Building. Access is by covered walkway from Terminals 1 and 2. Follow signs to 'Business Centre'.
Opening Hours 07.00 - 19.00 Monday - Friday. Hours may be subject to change. Closed: Saturday & Sunday.
2.
Airport LONDON,Heathrow
Terminal Terminal 1 International
Lounge SERVISAIR GLOBEGROUND LOUNGE
Location Airside - proceed through Passport Control, turn right at 'World of Whiskies' and take the lift/stairs to the 2nd floor. Follow signs along the balcony. Please be advised that the Lounge is NOT available for domestic UK flights and departures to the Republic of Ireland - International only.
3.
Airport LONDON,Heathrow
Terminal Terminal 2 International
Lounge SERVISAIR GLOBEGROUND LOUNGE
Location Airside - proceed through Passport Control, take the escalator/lift to the 2nd floor and follow signs along the balcony.
4.
Airport LONDON,Heathrow
Terminal Terminal 3 International
Lounge KUWAIT AIRWAYS - OASIS LOUNGE
Location Airside - through the main Departure Lounge and doorway 12A. Pass Duty Free and a set of doors and take the stairs/lift to the 1st floor. The Lounge is situated to the right.
5.
Airport LONDON,Heathrow
Terminal Terminal 3 International
Lounge SERVISAIR GLOBEGROUND LOUNGE
Location Airside - proceed through Departures into the Departure Lounge. Go through the doors towards Gates 2-55 and follow signs to Gate 12A. Take the lift or stairs to the 2nd floor, go through the double doors, turn right and follow the corridor round.
6.
Airport LONDON,Heathrow
Terminal Terminal 4 International
Lounge HOLIDECK LOUNGE
Location Airside - the Lounge is located at Departure Gate 17.
Opening Hours 05.30 - 22.00 daily.