Square Arches Linked on a Slope

We were contacted by Mr Furness to make 4 bespoke square arches with arch sockets as uprights and the recommended footplates to stablise the structure on a sloping site. The structures will be used to support rambling and climbing roses with it's crossbars and wires. Three square arches are linked together with the fourth standing further round the corner as shown.  

"I found erecting the structure on a slope difficult and it took me a long time, and I recommend that others find a level area. It is too early for us to comment on the quality of the product apart from saying we are pleased with the finish and think that the strength of the structure with roses growing over will be strong enough to withstand a gale. We have planted rambling and climbing roses. My experience of Harrod Horticultural has been mainly communicating with our Personal Advisor Jackie who was very helpful with trying to resolve our difficulties"

Mr Furness, Hertfordshire