Hi Andy,
Sounds like one of the good old Single premium policies, which you finance with your original loan. These are they type of policies that basically trap you with that loan until it runs its full term otherwise you stand to loose a huge chunk of the original policy cost should you cancel it.
Most companies will state that the only way to get rid of this type of PPI policy is to settle the current loan with PPI in full. They will more often than usual suggest that you finance this settlement figure by taking out a further loan from them without PPI.
You can always shop around for loans from other providers to get the best
Interest rate available to you. Thats what I finally did and reduced my
Interest rate from 8% APR Variable to 5.8% APR fixed rate. I am of course still fighting for the total refund of the PPI policy Amount plus
Interest as I was Mis Sold the policy at the time..Basically I was told no PPI then No Loan.
Good Luck
Ian