Odd name but great service and reasonable price, we have recently had a few new windows installed which we really like - http://www.1stfoldingslidingdoors.co.uk/
Thanks Peter, I've got a quote from them. Have sent you a PM - would be great if could see what they did for you.
I recommend Acorn Sash Windows on Green Lanes. They replaced my old sashes with double glazed sashes. They kept and renovated the old frames. I'm very happy with the result. They are considerate and honest.