nope, trim will do. just click inside of the circle that will make a hole. you can do that even in perspective view, just select the circle call trim and click through the circle on the object. in cases where the seam is right at this spot you may have to click on either side of the seam.
marry xmas to anybody reading along.
Trim deletes the part of the surface where you click. So if you are clicking outside the curve the portion of the surface outside the curve will be deleted. Click inside the curve and the portion of the surface inside the curve will be deleted.
thanks for your detailed help folks, very much appreciated
Ive got a lot to learn
Merry Christmas!