Be aware that even if the mil aren't using the range at weekends, there is a British Gas (or whatever they're called now) research site within the range complex. One of their specialities is testing gas pipes and containers to overpressurised destruction... They also have what looks like a mini oil/gas rig which occasionally gets encased in a huge polythene bag before several hundred cubic metres of gas is pumped in and then ignited. I remember seeing a notam for this, and the flying debris was planned to go up several thousand feet and out to a kilometer or so. The 'thermal bubble' from the explosion was notam'd to something like 30000'!
If they have a big bang planned they tend to do it on Saturdays at 1200 on the dot. An ex-RAF mate who was posted to Spade said that even indoors at the domestic site with the windows closed it was like someone had nuked the range.
As regards the 'silos', they are actually above-ground concrete test stands which were used for captive engine test on the Blue Streak boosters in the 60s. They can still be seen in the range, along with the huge concrete gutters for the cooling water cascaded onto the pads. One of the Blue Streaks is displayed outside at the camp domestic site. A government study was carried out as to the viability of using Spade as a launch site for Blue Streak/Black Arrow, with a polar satellite launch trajectory which passed over Kelso and coasted out at Berwick, with the booster landing in the North Sea just off the Norwegian coast. 'They' decided that it would be bad for publicity if one of the rockets was cut-down in the initial boost phase and piled into the Borders at Mach3 carrying several dozen tons of LOX and kerosene and used Woomera in Oz instead...
ST