Thanks Paddy Bloggit, I've decided I will move on. They were terrible to deal with and even when I made a complaint at the beginning they didn't acknowledge it. They didn't deliver all the windows on the day, they never rang me to tell me and I got no phone call or email to say when they would arrive. It was 7 days later before one of them arrived, others were still missing, then a window was cracked on the first day and they didn't replace that for another 2 weeks. They billed me for the balance and said the snag list was complete, one of the windows didn't even open! It took them 4 weeks from arriving at the house to install the windows until all issues were cleared up. Not once in those 4 weeks did they contact me to update me, I was basically left to guess when they would arrive. They arrived every Wed for some reason.
They offered me a discount of €200 for all of the above, which personally I think is a joke. I don't mind any company messing up, these things happen, but it was their management of it and one excuse was that they were very busy!! Two people that I know were looking for their contact names as they wanted to get their windows replaced, they will now be looking elsewhere!