Thanks again for the response all, I really appreciate it.
Am I right in saying that under "separate assessment" we could indeed transfer the credits?
This is from the Revenue site:
"What happens under Separate Assessment to tax credits not fully used by one spouse? Any unused tax credits (other than the PAYE tax credit and employment expenses) and standard rate band up to €45,400 can be transferred to the other spouse, but only at the end of the tax year. The increase in the standard rate band of up to €27,400 is not transferable between spouses. If you think you have unused tax credits or standard rate band, you should contact your local Revenue office for a review after the end of the tax year. It is important to note that, overall, the amount of the tax payable under Separate Assessment is the same as that payable under Joint Assessment"
If we can, I really don't understand why they denied us, possible mix up their end??
Will ring them myself tomorrow (probably to be told that my PAYE wife needs to make the claim again)