I do live in Cambs, yes:
(Greeny Blue line represents the A428)
I am 2 mins from where the A1 meets the A428 (presumably the route you'll take?)
My place is approx 30 mins from the meet point. I can suggest a meet point at the base of the A428 at Wyboston where you (and anyone else) would leave the A1.
We could meet there at, say, 11.15?
Gone but not forgotten:
325i M Sport (E92), Black Sapphire, Coral Red Dakota, 19" 225's, Seat Heating, 6FL and de-badge
Replaced by 6.2 litres of AMG powered C class.