Wow, thanks for your quick reply I guess I'll pay it, I was wrong in the first place not to close the account anyway

Hello, I was a student in the UK on exchange, so I opened an HSBC account. It charges me 5 pounds per month, because it is an international student account. I left the UK for Vietnam last summer without closing the account, because my friend told me if the account is inactive for a long time they will automatically close it, and so I just left it and haven't used it since. Trouble is yesterday I received a mail saying that I need to pay 50 pounds overdraft, and I should write a proposal to pay it before they formally demand repayment. 50 pound is not exactly a big deal, but since I'm not in the UK anymore I don't know how to pay it. My question is, as 45 is quite a small amount, will they simply write it off and close the account if they don't receive responses from me? If not, can I go to a local branch in Vietnam, bring my passport and card and ask them to close the UK account for me? Thanks for your help!