Cheers chaps

Sadly, Keith, have had to return indoors for the next bit, as the glue dries too quickly in the sun.

Yep, Nick, a couple of smaller bases will be good. I have in mind something like this from Amon Hen (?) , which would make a good platform for a beacon:

I’m struggling to come up with ideas for another. Boundary walls is a definite though.
And, James, I do believe you are right:

Edit: makes it more about the arch, less about the apex of the roof line