Avis - Heathrow Airport Question

Can anyone tell me if the Avis & Budget locations at Heathrow airport in London have been merged into one building?
I have a Budget Fastbreak rental and I think I have to take the Avis shuttle from the terminal?
Thank you in advance.

When I last rented from Avis Heathrow in January the Budget location was still in a separate building about 100m from the Avis building. The same (red) shuttles serve both locations and drop off and pick up from both. In the past when I have made a Budget booking but due to a delayed flight arrived after the Budget location had closed I was served by the Avis location with no problem. I have also returned a Budget car to Avis when Budget were closed. Avis operate 24/7 and Budget do not. Perhaps someone who has been more recently can update?

I was there on Friday. Budget is separate from Avis (although I'm not sure about out-of-hours arrangements). You will board the Avis bus and the driver will ask whether you are for Avis or Budget.

Just to add, there is a 'Budget' sign on the Avis shuttle bus as well.