The value you can borrow depends on:
How much equity you own.
Your credit history.
The total debt vs income ratio.
If you have a bad credit history, you can also consider a bad credit remortgage, available through specialist lenders.
Some mortgage providers will lend up to 90% of the value of your property (LTV), and often this applies to properties worth over £500,000. Others will set a limit as to how much you can borrow for debt consolidation, usually £30,000 - £50,000.
Different lenders will be less concerned about setting limits, and more about how the debt arose, and how likely it is that you have now resolved the situation.