Yes, it is a real problem for many dual nationals. The British banks do not find US resident customers attractive, due to the huge reporting requirements placed on them by the IRS. They often look at these accounts as a problem for not very much return.
As for the taxation, there is no problem filing but the extra layer of form filling required can be a headache as I am not in the UK, so I have to navigate THREE tax systems (two taxing worldwide income) and THREE different filing and payment dates. So far I have managed it perfectly and never been late or missed anything however it is A LOT. Then when you add in the extra dimension that inheritance tax might create for me in a few years, it feels overwhelming. The key issue is America is one of only TWO countries in the WORLD that demand citizens file taxes regardless of where they live. It is a royal pain. We never owe anything to the US as the taxation is higher in Spain, but still, it costs us a fortune in time and money to remain compliant.
As for visas and future entry I will definitely take legal guidance on that. Though I never want to live there again (and could likely never afford to again what with housing and healthcare costs) I would like the ability to holiday there. I will take some advice and try and best weigh up the pros and cons. Thanks so much for y our help and input, I really appreciate it.