Mr J is a lovely chap, he's an ex-engineer though and through experience working with engineers can be a trifle difficult. Not because they're an unpleasant bunch, far from it in this case, but because they know exactly what they want. Almost, but not quite, as demanding as architects.
Having said that, without the knowledge of his property that Mr J possessed, we would almost certainly have encountered problems. The property was a stunning early 1900s place and yet the sun lounge that we were installing to was an extension. Mr J advised that we were not to install the awning on to the building and that he had calculated how the awning could be fitted 'free standing'. We were to excavate a patio again (not for the first time!) and install two 60mm x 60mm stainless steel posts with an 18" x 18" steel plate on the bottom. The plate would be sunk in to the ground and would have a yard of concrete laid over it to secure. It worked, and the awning looked great. The most satisfying thing was that Mr J didn't realise the brackets were in place after we'd filled the patio back in, they blended so well with the wall.