Assuming you have an Italian bike on the day and have selected a display ticket (free of charge), then use the Campbell Gate Entrance off Brooklands Road. The postcode for SatNavs for this entrance is KT13 0QN. This entrance is shared with JTI and signed ‘JTI Members Hill’. There are various restaurants/cafes and shed areas to select to meet. The Clubhouse building is quite central (red 7 on the image).
Looking at the info on the website it looks like you still have to pay the full entrance admission then add Italian vehicle for display.
The usual parking spot for the Italian bikes is in front of the BP pagoda shed (no 4 on the map/legend shown in Bridgland post above) which is where I shall be heading on Sunday morning - hopefully see you all there.
Just go back into the Brooklands website login and add a ticket for displaying a vehicle - free of charge - job done.
Looks like i'm going in my Alfa Romeo Stelvio. Traded both my bikes in today for a 2021 Diavel 1260S arriving Friday next week. Cracking deal I couldn't say no to.