Presumably HSBC objects to a for-profit business running a patreon & donations. I can see how from a bank's perspective that could look like something illegal is going on.
That's something they can complain over. Or hook you up with the local attorney general. Or shut down your account on some bullshit excuse to make you make it someone else's problem.
Silently freezing the account with no way to resolve it? Nope.
That should have come up on the initial review if it was a problem.
It could be the tax office, since getting money from Patreon (and also Kickstarter) counts as taxable income.
As a business with an accountant I would assume all applicable income and expenses are recorded correctly