"michael adams" wrote:

If you go to the bottom of your garden, and taking advantage of the 6-8
inches
offered by the positioning of the fence can't you take a photo or series
of photos
one of which will be exactly at right angles to the back of your house ?

I have tried that but the result isn't as clear-cut as I would have liked,
partly because I can only get such a picture from the farthest point of the
garden and at that distance, even with computer-aided enlargement, it's not
easy accurately to mark the exact line of the border.

But I'll persevere. Thanks for the thought.