Re: Backups and redundancy, FFS
"I always carry £100 cash in a separate compartment for circumstances just like this."
I do the same thing, Especially for longer trips out of town. That way I know I have dosh for petrol (if I'm driving) and some money for meals.
A friend of mine had an embarrassing moment when his deadbeat wife got a credit card sent to her on his business credit account and went on a big shop. He happened to be entertaining clients when his card was declined as over limit. I can't remember exactly how he resolved that at the time (other than the divorce which wasn't his idea).
Digital currency and payment methods can go titsup at any moment for hours or permanently. Having cash on hand is an easy insurance policy. Get a safe and then stash some backup elsewhere in the house (make the safe not too hard to find. Bottom of the wardrobe or someplace like that). If anybody breaks in, they may just nick the safe thinking thinking they've got all of the best goodies.
Lastly, it's much easier to stay on budget if you do your daily transactions in cash. Decide what you can spend each day for misc. stuff and only put that much cash in you pocket. Also, get a separate bank account to receive pay deposits and for what you may use to pay bills online then leave the debit card for that account put away at home. Use a secondary account that you top of from time to time to have a debit card you can carry around. If you get jacked up and forced to get cash from an ATM, you won't be risking your main account. You also can't make an impulse buy for too much without having to make a bigger effort in accessing your funds. Cash doesn't take electricity or a network to work.