More likely to be concerns about non-EU business. Assuming it's not phishing and you're above board, there's nothing to worry about beyond the usual concerns over government over-reach into our affairs, and there's not a lot you can do about that in the short term.
If you move to a different bank, they will ask all the same questions when you try to open an account, so telling Barclays to fuck off doesn't really provide any benefit.
More likely to be concerns about non-EU business. Assuming it's not phishing and you're above board, there's nothing to worry about beyond the usual concerns over government over-reach into our affairs, and there's not a lot you can do about that in the short term.
If you move to a different bank, they will ask all the same questions when you try to open an account, so telling Barclays to fuck off doesn't really provide any benefit.