Lounge access during connection

I have a flight booked from LAX to TLV with a connection in LHR. Originally booked premium economy but I paid for an upgrade just for the LAX-LHR leg to upper class. The upgrade states it includes access to the Lounges.

When arriving to LHR @ 10:40, will I have access to the main lounge or just to the arrival lounge (as I understand I must go via passport control to access it and it is only open until 13:30, my connecting flight is at 16:05)?

I have red membership.

As far as I know, you will have access to Revivals only, and yes, it is outside the the "border", so you will have to clear immigration and customs. Access to the Clubhouse depends on the outbound flight from LHR, but you could always try, the staff at the door have been known to exercise their discretion in favour of pax from time to time, or give you an option to pay for access.

The Clubhouse quietens down after midday, so that will help your cause. If this was me, i'd do the following:

• Try and access on the basis of your Upper Class flight from LA.
• See if there is another Upper Class upgrade available for the TLV leg, either with Cash or Miles which would automatically grant access.
• Offer to pay for access - can be done for around £65 on a discretionary basis, when the Clubhouse is quieter (not possible during the morning rush period).
• Plead with the lounge dragons.

Best of luck...