Vandalism seems common at certain stations. Burley Park Station in Leeds can't have a TVM that accepts cash apparently, because of constant vandalism.
How the metro systems of this country with unmanned stations/stops (e.g. Tramlink, Metrolink, T&W Metro e.t.c) deal with this sort of thing must be interesting.
I don't know about robbery figures but I have heard of quite a few cases, hence why ticket machines outside in a car park may have bollards to prevent them being rammed by a car.
Info about a case here
Same reason why Steeton & Silsden has a card only machine. The last time it got a cash ticket machine it broken into at least twice. After the last time, it was removed.
That CCTV at Denham is classic.