Allotments 4 All

We have a thief on our allotment. We know who they are because they were eyeballed in the act, but by somebody that prefers not to get involved. We have spoken to the police about the legality in putting in surveillance cameras and they have told us we can go ahead, with the caveat that there must be a sign at the gate saying the allotment is CCTV protected.
All well and good.
However, a group of us went to Maplins and had a long chat with the staff regarding suitable cameras. We understand that we will have to power any device off of a car battery, which is not a problem. But there don't appear to be any suitable outdoor cameras available.
Have any of you used small cameras on your allotments or know of anybody that has?
We would like to know the model number of any cameras that you may have used and an idea of how successful they were.
The problem is with many available units that they will use flash at dusk (which would mean the thief would suspect that they were being watched and probably smash the camera), or are not really waterproof or will not give good image quality over a reasonable distance. The biggest headache is how information from the camera is stored. We have found one with an SD card, but most of the others are more suited to transmitting to a shore-based capture unit, which is impossible in the middle of nowhere!
Any advice you can give welcomed!

The thieves would probably also visit the site in daylight simply to plan where to pay their night time visit, and would probably see the CCTV cameras anyway.  The knowledge that the site is so protected may be sufficient to deter thieves.

However, have you considered mere deterrent.  Several movement sensors coupled to flash units placed separately would equally convince the thieves that they had been pictured, but there would be no camera to find, and a number of different flashes going off in all directions as the thieves ran off should put the wind up them  a bit more than somewhat.  It would be very much cheaper.

The type of camera we are aiming to deploy would not be obvious to anybody. They are tiny!
We are adopting a number of measures, but we want to trap a particular person, so need to know whether anybody else has used cameras and, crucially, what make they are.

If you already know who it is, and you simply wish to prove it, then why don`t you simply take it in turns to keep a nightwatch, armed with a proper photographic camera and flashgun until you cath him?  Save you a lot of money in the long run.