Hi Alan,
Congratulations on your 7mm layout so far. I 've only just discovered your thread, so please forgive me.
I have seen some layouts at exhibition with roughly the same space where there is something like a private business siding, platform,or whatever you want, coming off on the left of your layout, going in front of your sector plate, adding more operating potential, while the sector plate is hidden behind a small backscene & overbridge. Don't know whether you have considered this, but I wonder whether this would make the layout more interesting & varied when it comes to operating. Just a thought, before everything gets fixed down.
Good luck with it all, I look forward to following developments.
Cheers,
Steve