Just for future reference for anyone that has a similar problem:
Car went to a local bodyshop at the expense of the dealer I bought it from, he found that a non genuine window regulator had been fitted which was both too stiff and broken, he's fitted a genuine regulator and has told me that the windows no go up/down when the door is opened/closed, hopefully the convenience windows are now working too, I'll test this when I get the car back in a day or two.