Ebay sell seat covers for a c max , just type ford focus c max seat covers in search space and they come up.I think you have to be carful with seat covers on the front as it is dangerous if you have an air bag in the seat.
I also had my new cmax two days ago and wanted seat covers, only bought two for the front so far, they are wipe clean ones and only costed £4.97 in Tesco Xtra. The same ones in Halfords are at least a tenner, Tesco do not have rear covers, but it may be worth buying seeing if they will individualy fit the rear seats, if so buy three packs, you'l have a spare cover and also will of spent less than £15.00.
You can get much tougher and stronger ones for around £20 in halfords.
Tesco Xtra is worth a look.
My wife has just got the new Woolworths Xmas gift book.On page 334 item 2 there is a set of front & rear seat covers with 5 head rest covers.The rear cover has a zips for`split seat` options.Price is £26.99 cat no 252012040.you can get these from Woolworths website with free delivery.Exellent offer especially as it`s got the zip option!