Fort halstead

I have some very very good sources in britain , but this base Fort Halstead is known to exist , the goverment says it does , it has a website etc etc BUT it is claimed to only have 5/6 strories going underground
My source , whom has been in every major conflict since 1979 invloving the british armed forces , he has performed around 50 HALO insersions been in the MI5 building and lots more

but this base claimed to go down a mear 5 stories actually its goes down to a near 35/40 stories , despite this man being allowed to MI5 etc he wasnt allowed past level 10 what exactly could be down there , is it supposed to be a weapon storage center

Fort Halstead,

Repurchased by Ministry of Defence in 1937 for work on anti aircraft rockets and currently within the boundary of DERA Fort Halstead, an MoD research establishment.

cant find anything decent on google,35 to 40 stories ? wow-would you care to mention what regiment or organisation your source is involved with?- im thinking SAS? or Pathfinder?

Regards.

I honestly don't know i rarely get to speak to him because i live on the otherwide of the country so i only get to see him like twice a year i'll try to find out ASAP