I've just had a letter from Revenue in relation to TRS on our mortgage. We use our house partly for business and claim 80% of the interest in our accounts. The remaining 20% is eligible for TRS as it is our main residence. We submitted the form to Revenue in 2006 advising them of this split. Now having looked at all the bank interest certs from 2006, it appears that we have been getting TRS on almost the full interest - something like 90% of it. The Revenue are now asking us to confirm the split. Given that it appears as if we have been getting too much TRS all along, will we have to pay it back? Also, our mortgage is shown as a commercial loan on the interest certificates so surely the bank should not have applied the full (almost full) TRS - do we have any comeback with the bank? I don't know why the correct TRS was not applied back in 2006 when we submitted the relevant form to Revenue - I suppose they will say that they never received it.