British S-Mine training aid

[BMG50]

I have just been given the top half's of the pictured mine, which is a British WW2 training S-Mine. At first i thought that the filler and det caps screwed off, for training how to diffuse these mines but apparently not so. It seems that these mine are fitted with a pressure switch N0 2 that sets off a delay cap seen protruding from side of mine, used for stepping on rather that defusing. The top half all made in brass the bottom made from a type of concrete, a cork shipping plug seals the centre nut with the pressure switch cast into the concrete below. It looks as the switch could be used again and again by undoing the brass collar that is sealed with a red rubber washer when not in use, at this end the striker firing pin is pushed back to re-cock the switch, a new live cap replacing the old one that sits in the brass collar.
Anyone have any reference on this training device, how it works etc. I would also like any reference on pressure switches, which i think i may have, but not sure.

 

[BMG50]

Well i dug out the camera and took some pictures of the training mine i have. As you can see the top plugs are soldered in place. The top of the mine is screwed to the concrete base (well a kind of concrete that is made of the same material as the dark grey breeze blocks with the black bits) with brass screws into wooden plugs. The original shipping cork can still be seen. The pressure switch as mentioned before doesn't have a blade but has a modified catch or pin that engages the firing pin that can be repeately cocked and re-used again, the firing pin seen broken at the part it engages. the brass cap on the end holds most probably a det cap or something to set it off, clearly not a training aid to diffuse one but made to be set off under conditions etc. One of the pictures shows the original red rubber shipping seal. The last pictures show the switch in its original position set into the cast when made.
I am sure that there were igniters to set these mines off. Can't find much about them. The original colour was an olive drab. Any one have any info.

 

[BMG50]

More Pic's.

 

[spotter]

strange item,never seen anything like that before,interesting piece of kit