I did some research and decided on purchasing the Browning Recon Force Edge from the Nature Spy Shop. This offered all the settings I needed including the ability to set the time period the camera works for. This saves on battery life.
Once the camera arrived I set about making a secure box to house it in. An old metal electric box was perfect after some modifications. I am really pleased to say the camera was bone dry despite the horrible weather we have had over the last few days.
Anyway I retrieved the camera first thing this morning after three days. The batteries were still doing well at 75% and it had recorded something.
I swapped the memory card and secured the camera back in its box and left it to do its work.
Once downloaded I was pleased with the results although perhaps for reading rings the camera needs to be closer to the big tyre. I did move the tyre slightly, so we'll see next time.
The hope is that I will be able to read some colour-rings, but that will take time I think.
Here are some of the results: