The unit depot canbe seen from the station also via a foot-bridge accross the main line also from a road bridge that crosses the line at the top end of the yard about 90% of the numbers can be got from these vantage points all with-in easy walking distance from the station.
As for the withdrawn stock at the MOD base quite a few numbers can be seen with bino's by driving around the perimiter but not all head out towards Foulness to the MOD checkpoint and the security man will let you use the road through to the sea it is open to the public a lot more can be seen by parking at the end of this road and walking in both directions along the public footpath A car is essential to reach this point as it is a long walk
PS dont mention the bino's at the checkpoint the guard saw mine on the seat fortunatly he turned a blind eye but a different guard may not be so accomodating - what they don't see they don't know?