Hi Swood,
It's a tough one trying to get that finance sorted. Have you tried several branches of HSBC? You may get different responses from each.
There has been more than one extensive thread on this topic (run a search on HSBC and Loans and you will find a lot of info) I believe it is possible to borrow more than that but there are implications on APR, security, discretionary terms etc (I won't go into detail as it is covered very deeply in other threads!) Have you thought about using a Career Development Loan in addition to a Professional Studies Loan? That will supplement your total by another £8-10K. Have fun reading the other threads and Good Luck!