Hi, i recently was in the exact same position wiht my father, Basically he had an endowment mortgage that was not working for him. He might as well have been putting the money under his mattress.
Best solution and the figures support this is to get on to an annuity mortgage and make your money work for you. I ended up saving my father thousands plus you are no longer worried abiut the "performance" more like nightmare of the endowment policy.
Most useless products ever.... back in the day when interest rates were high they may have been good for certain people but in todays climate its better to cash it in, get a straight forward annuity mortgage and clear off the mortgage without having to worry about how much you owe in ten years.
Its amazing the amount of interest you will save on the mortgage amount itself.