Yes I definitely got a good deal on the karndean. It was from the Van Gogh range. I don't have toddlers so can't comment! It does seem very hardwearing though. I changed the bathrooms from vinyl to karndean at the last minute and they said just to add £100 rather than working out another price. Nice! The builder gave consent for 2 days of carpet fitting and karndean prep prior to completion. I had to request this through the solicitors. The karndean glue didn't dry quickly enough so on the day I moved in, it was still being fitted. The removal men were climbing over the karndean fitters. It then took another 4 half day visits before it was completely finished. It was worth it but I just thought I'd share this info to help you plan you flooring fitting in the new build.
Talk to them, get a price, ask for a discount based on the fact that its a reasonable sized job, ask if that's the best they can offer, then leave saying that you need to think about it / get some other quotes. They'll have at least 1 or 2 steps down that they can take, so make sure that they take them!
I am moving into a new build house next month and need to carpet throughout... would it be rude to ask the carpet shop for a discount if I was buying carpets and underlay for four bedrooms, lounge/diner, hall, stairs and landing as well as them fitting it all. I'm looking at over £2500 and that's before I tile two bathrooms, kitchen and utility.