Thank you very much for your replies guys, some very interesting ideas which I will definately look at when the project developes, for the moment I will draw in a symbolic representation using lines as its too much time at this stage.
Sart, thanks fo rth etip on imagecad, i guess I have to pay for this? Im disappointed that something as basic as this should have to be paid for as an extra, when brick arch is already available, why not a surround for the whole window?
Regardless, many thanks once again for your help generous forum users!