These sound like reasonable ideas but what are you going to do when you run out of petrol hundreds of miles from home with no cash on you and out of banking hours? With a £20 limit on cash machine withdrawals you would be stuck unless you use your credit card and depending on your car even that might not be enough if you have a £50 limit on it.
Personally I'd rather my bank increase the amount I can take out of the hole in the wall because it is regularly too small for me. But I do like to deal in cash, even for large purchases like a TV or furniture.
The best idea is what my bank does already, and my previous bank also did. If my card is used outside the UK it is declined unless I have phoned them to say I will be away and even then it can only be used in that country. Takes 5 minutes and can even be done from abroad if you forget before you go.