I think aissecur is correct it's a old dennard motor well done and many thanks thismwas amoicture from a programme in the 1990's and I was curious what unit they had used
What about changing the fixings for the mag locks.to the frames to security screw type fixings with none standard heads or needing.the proper tool.for.the screw or.bolt removal
there should be a key left by the unit or with you from the owners, if not pm me your address and ill send one in the post, a small shaped keyhole on the unit is where the key fit and you just twist the key to push the trigger button back to break the contact.
if its an analogue system like whistle says run 8-10 cat 5's and patch each cat 5 camera signal to the pair on the new cat5's in a big junction box, then balun on end to dvr.
http://www.netshop.co.uk/product/90/6468-5-080-00
roof trusses shouldnt be drilled due to their sizes not being large enough they are designed to have no drilling lor damage done just to support the ceiling boards, they arnt meant to be drilled and weakened.
just to show the quality of the ir and camera from the ir speed dome bearing in kind its virtually pitch black outside with no street lights local to driveway.