This is a slightly different way to solve this use case but we now have a way to get the same result 
The app doesn’t let you spend money from your Pots (out now for users of the test app so coming very 
) so if you’re going out, just transfer all the money you don’t want to spend into a Pot & then your remaining balance will be all you can spend 
The only thing is, there doesn’t seem to be a workaround for this problem
so if your battery dies, you’ll have to find another way to contact the support team in order to spend the money that’s in your Pots..