Thanks for all your responses. In the end we took a mixture of cash and cards. There was an ATM on arrival at the airport which was coonfusing to use but in the end spewed out currency and gave us back our card. Banks did not really look like banks and could be tricky to find. In the end we mostly used ATMs and changed sterling to CUCs in one bank. One hotel would only accept euros or US$. So sterling not universally accepted.
Well, well. Is it ‘global warming’ or ‘cloud seeding’?