I've realised our arbour is out of alignment - I can easily pop a jack under it to straighten up, but I'd aligned it to the fence post. What's happened over the years, is this one post has leant, and the fence moved with it. Since putting in new panels, the post is out by an inch over 5ft, and it's now 'noticeable to me' that the arbour isn't quite straight. Grrrr, can't jack further as the roof is flush with the washing line post that's mounted to the wonky fence post.