I’m annoyed (UK)

I DCA into Bitcoin on Kraken Pro via Nationwide bank regularly, and today I deposited a larger sum than I usually do (£1000). It got held up for 4+ hours until I received a phone call from the Nationwide fraud team. I got asked a bunch of questions, and it felt like they were trying to work out whether I was falling victim to a cryptocurrency scam. I get that part - but why am I being asked these personal questions? They made me feel quite uncomfortable, like they were fishing for information that wasn’t necessary.

“Why have you chosen to invest more into cryptocurrency than what you regularly invest?”

“How much money have you put into Bitcoin overall?”

“Why are you using Nationwide for cryptocurrency payments, and do you plan to keep doing so?”

“Do you have a financial advisor?”