Thanks a million. I'll clarify a few bits. In 2006 loan was split 1/3 tracker and 2/3 fixed for 2 years . After 2 years in March 08 I was only offered fixed again or variable for whole loan amount not split so I fixed the whole 3/3 for 2 more years. The rectification will be on the tracker 1/3 presumably because I should have been offered it again after fixed period. The 2/3 was never on a tracker nor had entitlement to one I think . So since 2008 the loan has been treated as a whole and on fixed rates. When I made the overpayment the whole loan was on a fixed rate.