Tim knows more than me ... the only things I can add to what have been said is that provided you have been paying your loan to HSBC on time, they may be able to extend the term of the loan so that you will be paying less per month (but more in the long term) on this particular loan. Be careful, however, that they do not treat this a variation (?? term) or anything that will be recorded on your credit file - if you do do this option, then have it in writing from them that this will not occur.
Another 'trick' is if you do have a credit card with no balance on it, or you can obtain one, then put as much of your monthly expenditure on it as possible, ensuring that you do pay if off in full. However, you should only do this if you are disciplined enough to pay if off. If you do do this then you will effectively be getting a free loan.