Thanks all for the advice. We have not used the choker i just don't feel safe with a dog chained with one.
I would love to have a undercover Dog run but we are currently living in a rental and we have made a dog run that we can remove after we leave. I am looking to buy my own house at the moment and will be building undercover run for them.
We have found a temporary solution. We found that part of out problem was the type of collar. she was wearing the ones that you have to slide to adjust but we have switched to a collar with a proper buckle. When we put her on the chain we do up an extra hole that normal and she can't slip it.
However I don't like leaving her like this long term with a tight collar, even tho she can still drink and eat, so we have ordered Martingale Dog Collar (as suggested by Keira & Phoenix) from our vet as well as a new harness for walking and the car.