Personally I would not keep using an HSBC account. As you say, historically, they have, with alarming regularity, closed accounts, without notice, when a customer has enetered an IVA.
I would say that, over, maybe, the last year or so, these reports have diminished to only the odd one here and there.
If you are comfortable that you could manage without access to bank funds for a week while they refund you the account balance then all well and good. I would suggest making one of your other accounts the main centre of business, just in case.
My opinions are merely that .. opinions based on experience. Always seek professional advice.
IVA Completed 23rd July 2013 .... C.C. 10th January 2014