Question

Over 10 years ago in order to entice me to move to London my company lent me £125,000 as a half payment towards a property. The deal was that I did not need to pay any interest on the loan but on leaving the company I would either have to repay the loan with interest or sell the property and share the proceeds. Over these last 10 years or more my annual tax return included a tax charge for the benefit in kind for theinterest-free loan represented. Two years ago I was made redundant and elected to repay the loan. As a concession I was given 2 years to repay the loan in 4 installments every 6 months. The amount to be repaid includes compound interest over the full term of the loan based on interest rates current each month. For the initial loan of £125,00 I was asked to repay just less that £200,000. If during the term of the loan I was taxed each year on the fact that I was charged no interest can I claim that tax back now that I am being asked to pay that interest retrospectively? Thx