These Clicky are the bunkers you are talking about? covered up by trees. Would love to know whats in them if anything anymore, maybe you should dig them out lol.
I can shed a little light on this picture.
The construction approximately 40mm to the right of the minus sign on the sliding scale was a powder magazine together with the one just above the word "infoterra".
These were mounded up on three sides and measured approximately 8ft square. There was around 5 - 6ft of headroom as I recall. The strange thing was that each magazine had double doors, when you opened one set there was another immediately behind it.
The doors opened onto the River Stour which is what you can just about see on the left hand side of the picture.
These magazines were used for storing bought-in powders, we used to use a lot of gunpowder and, in the earlier days, electric igniters although new stores were built later on elsewhere on site.
Above these about halfway up the sliding scale on the LHS are two more mounded enclosures, this was the "dump" where factory waste was burned off, the first one was for inert waste the upper one for live. The burns were a bit lively to say the least on occassion!
The magazines were blockwork built and rough rendered, they looked ancient but this end of the factory was not where Astra originated, and I believe they were added to the place in later years, if I were to hazard a guess I might say in the 1950's - but this WOULD be a guess.
I'm sorry to disappoint you lot but there is nothing in there. When the place was decontaminated these two places were absolutely gutted, the linings and floors were ripped out just as they needed to be.
As an aside. The place was built on what was once a former re-settlement camp for dis-possessed aliens, i.e. Jews etc. at the outbreak of WW2. persons who were alien to the U.K. but who couldn't be re-patriated were accomodated there. It was also part of a larger collection of camps built to handle outgoing troops leaving England for France.
Included in these installations were magazines for ammunition, presumably destined for overseas conflict and awaiting despatch along with the unfortunate and incredibly brave young men assembled in these parts. I recall as a young lad working there, being sent across the river to conduct live firing tests deemed too dangerous for the tight confines of the site. In the course of doing so, one of the elders of the factory, a chap called Larry Oliver - very knowledgeable (I wish I had listened more to him!!!) told me about the wartime magazines and had me look around on the opposite banks for evidence of them, their location had been long lost and he was keen to establish whether or not they had been there.
There were some remains there, I couldn't say what they were though, as for the two gunpowder magazines - I understand on very good authority that owing to the way they were mounded some of the lazier chaps in the factory used to skive away from their duties and sunbathe on the roofs.