Here you go, I borrowed this from the AROC site:
The Alfa Romeo Owners Club Essex Section are hosting Southern Alfa Day on 24th September at the Royal Gunpowder Mills and would like to welcome all members to this historic site to enjoy the many displays and exhibitions to interest everyone. It is spread over a large area as buildings were separated due to the materials being processed and wildlife now thrives on the site. The many attractions are shown on the Royal Gunpowder Mills website, and include 170 acres of history, the Rocket Vault and the Armoury, just to mention a few. Land Train Tours of the site are available for a small extra cost. And, of course, our cars will be on display.
In the theatre, Ken Carrington will present his illustrated 'History of Alfa Romeo' during the day.
We will have our own entrance to the site, opening at 09.30 hrs, and recommend that members use the Club's online ticket facility, as at the gate we can only accept pre-paid tickets or cash. We will not be able to process credit/debit card payments. Please print off the pre-paid tickets for collection at the gate and, if you're paying on the day, have your membership card available, especially if you are not in an Alfa. Advance tickets for members ar just £8 per adult and £6 per child (5-15 yrs). Non members advance and all tickets (members/non members) on the gate prices are £10 per adult and £7 per child.
Also the gate will not be manned after 14.30 hrs and anyone arriving after this time will have to use the public car park and pedestrian entrance, but to be able to see the attractions at the Mills, an early arrival is recommended, last entry 15:00 hrs.
Unfortunately dogs are not permitted on the site due to the wildlife living there, except registered Assist Dogs.
There is easy access from the M25, junction 26. Take the A121 to Waltham Abbey, and at the cross roads and traffic lights by McDonalds, go straight on to Beaulieu Drive. The Royal Gunpowder Mills is at the end of the drive.
Tickets are available from the homepage
or by calling Club manager Nick Wright on 07753 857029 to order over the 'phone.