From memory (and it's hazy since I think I did the SA in 2008 and 2011 ) there was the petrol station / truckers area when you first cycled into Membury via the access road, which had its own shop but hardly any area to sit/wait. But if you cycled on to the main services building you could stick your bike inside and then up the stairs (or was it a turned off escalator?) to the cafe area which has said manky carpet.
In 2016, when I was reasonably fit, I got back to Chalfont at 10:20, easily my fastest 400. I can never do it again as they won't let me do the last section down the A4 / I would be several hours slower.
From memory (and it's hazy since I think I did the SA in 2008 and 2011 ) there was the petrol station / truckers area when you first cycled into Membury via the access road, which had its own shop but hardly any area to sit/wait. But if you cycled on to the main services building you could stick your bike inside and then up the stairs (or was it a turned off escalator?) to the cafe area which has said manky carpet.