Your sale of shares is subject to Capital Gains Tax. A CGT loss can only be set against a CGT Gain.
The DIRT that you have paid is on Deposit Interest which is subject to Income Tax. People under the age of 65 are not entitled to a refund of DIRT even if they have no liability to tax.
Joe_90, I'm a bit confused, to quote you "The DIRT that you have paid is on Deposit Interest which is subject to Income Tax". Is it true that once DIRT is paid on deposit interest that the same deposit interest is not liable to any other tax?
Deposit Interest Retention Tax (DIRT) is a withholding tax it is not a tax in itself.
Deposit Interest is Subject to Income Tax under Schedule D Case IV.
It is different to other sources of income in that it is subject to tax at 20% 23% or 25% depending on when it was received.