Adverse credit history.
Arrange a mortgage in the current financial climate is much more difficult that a few years ago. It may be that your lender was happy to lend to you when you took out your mortgage now they will not consider a remortgage or further advance.
However there are many second charge lenders how will consider people with less than perfect credit history.
Although these rates will be higher than your current mortgage you may only need this loan until your credit history has improved CCJs and defaults only show on a credit file for 6 years. So it may be possible to raise the extra funds you require, possibly on an interest only basis to keep the payments affordable. Then put then refinance the mortgage and loan on to a repayment basis once your credit profile improves.
One of the first steps to obtain your credit file so you are aware of exactly what your issues are and also how long they will be recorded.
Many second charge lenders are more flexible in their approach; they tend to look at your current position and your ability to afford the payments going forward, rather than a situation that occurred in the past. They will also look at the reason for the previous problem events such as divorce, illness, redundancy. Many people who have had previous problems are more careful with their current financial affairs.
It may also be the case that as property values have increased there is more equity in your property which improves the security for a new lender.
It can be possible to consolidate other finance typically credit cards where not only are you paying a very high rate but if you only pay the minimum payment each month you are paying a minimum of the balance, many cards are set up so that with a minimum monthly payment only a very small percentage is paid of the balance they can technically be said to be on a repayment basis but in reality are effectively interest only. For a similar payment with a second charge loan the balance could be paid off, the term would dependent on your budget.