Following on from CocoPops post
Leaving J14 of the M1 and then follow the A509 to Newport Pagnell and onwards to Olney, this will eventually take you to a roundabout with the A428/A509 (you need to continue on the A509!!) and across from this roundabout and on your RH side is a large petrol station (I believe its a Shell station)
Maps here and here (will post decent pics when I have access to my FTP)
Let me know the times you want to be at the Pod and I will amend this post as necessary
Cheers
Iain