Agreed Peter. Uncertain as to availability, but if I am will certainly make the effort. Are you still contemplating a switch from GS to GT, if so it'd lend added benefit for the meet?
Kemble is fine, but just heed the warning of fine weather, lots of movements attracting loads of spectators -> jammed car park.
Can't think of a venue that's more interesting/convenient/accessible pub with decent car park. I'll ponder further.
The Eliot in South Cerney would accommodate four or five cars, location OK, pub a bit basic