Capaill said:
You are obliged to be given a a period of 7 working days to cancel the contract with the supplier without you having to give a reason.
(All assuming you bought this from Irish site).
I would actually dispute that this is the case for purchasing an item online. The information linked to there is for a service, and cooling off periods normally only apply to things such as investment products etc (in my opinion only).
When you buy an item, you can return it only if it is broken, or doesn't fulfill the purpose for which you bought it - Sale of Goods Act.
Just because you don't like what it is now that you've seen it, you don't have an automatic right to return the good - it's like you suddenly discovering that the clothes you bought aren't really your colour after all.
In this situation, you're purely dependant on the goodwill of the supplier.
(Applies to whether or not you bought off Irish site).
I would let them know you're difficulty. Ask them if they have a suitable alternative and see if you can take things from there. If you get an alternative from them also, they're more likely to refund you the difference rather than the whole amount.