Ok easy way is M25 south take junction 28 (Brentwood) follow the road right up the hill etc go past all the shops you will come to two mini roundabouts opposite a big furniture store (mr Coopers I believe) the corner is called Wilsons corner, turn left and go straight ahead at evey mini roundabout you will come to a pub on the right called the Robin Hood or Little John still got the connection keep left, carry along you will come to another mini roundabout, bear right and just stay on that road go past the Eagle Pub (on the left) you will soon see one of those Brown tourist sign for a nuclear bunker, thats the the turnoff you are looking for, follow the road thru the field and park up ...now ya there. All of this travelling from the main road will take about 10-15 mins tops so although it seems difficult with all the landmarks etc it is easy. there is another way that is slightly more direct but get it wrong and you could end up in a totally different place so take the main Brentwood turn off from the M25.
Get there for around 8 am captains meeting is normally 9 am