Superb!!

Many thanks Doug, and also for the link. Although it is not happening in the next few weeks I will be attempting the first try at landscaping and have been looking at the options on youtube. I'd seen the spray foam method which I'd already thought of to be honest but with the scale of T I think it's...

Looks brilliant Doug, is that the wall foam you mentioned to me by the way? 2"? If so it really does do the job. Great work!