Unexpected refund back from Revenue

I'm a PAYE worker with one small investment property so I complete a Form 12 every year, I also submit a Med1 form if I've any medical expenses. I had expected to pay some tax to the Revenue for the investment property, last year I owed them €168 but they deferred it due to it being a small amount, the reason the tax due to them last year was so small was because I was on Maternity leave for most of half of 2003 which brought my earnings down. I received a refund cheque yesterday for €1,400 which I felt had to be wrong, when I looked closer at my Tax credits it appears they've given me the €3040 (married person 2004 credit), I am married but I remain assessed as a single person, I gave them my husbands PPS number on the Form 12 because they asked for it but I've never told them to assess us any differently. I can't get through on their phone lines but what I wanted to know was - I take it this is a mistake on their part and I that I shouldn't have been given the €3040 but indeed just €1520? If they keep it at the €3040 do I need to submit all my husbands P60's from past etc.?

Thanks ...

Revenue do make mistakes, and pleanty of them. They assumed that you wanted to be put on married assessment. You will need to contact them and explain the situation, and they will be able to revise your details to show either you on single or joint assessment.

Why do you want to be assessed seperately if being assessed jointly saves you money? Especially in a year where you were on maternity leave- you can always go back to being seperately assessed later when you are back on full pay if you are then both on the higher threshold.