Refinancing Master

Following recent news, I discovered that the Bank of England lends money only as the “lender of last resort”. If the BOE does not reguarly lend money to banks (i.e. my mortgage is not underwritten by BOE loans) why does BOE base rate have a direct effect on my mortgage?

I have 12 more payments and my car is paid off, but I’m a college student, and making the payment is really hard. I dont want to mess up my credit, by ending a long history account (my current auto loan) and opening a new loan. Any suggestions?

I don’t owe that much, and I have no trouble with my current monthly payment. I don’t want to refi if there’s a negative impact on my credit.