8.30 is good for me, this is where the Portobello Inn is, even done the directions from the M25 for you I have a feeling that you maybe coming anti clockwise though. Easy enough take Jct3 then the A20 towards west kingsdown & Sevenoaks, drive about 2miles, pass brands hatch and a texaco garage and its on your left hand side on the junction with Fawkham Road.
http://maps.google.co.uk/maps?f=d&sourc ... Inn+(o%2Fs)+station,+West+Kingsdown,+Kent+TN15,+United+Kingdom&hl=en&mra=ls&sll=51.341256,0.267448&sspn=0.007211,0.022724&g=West+Kingsdown,+Portobello+Inn+(o%2Fs)+station,+West+Kingsdown,+Kent+TN15,+United+Kingdom&ie=UTF8&ll=51.366315,0.243244&spn=0.060339,0.181789&t=h&z=13
Thats of course were meeting there