Well I wasn't happy with what I had done so up it came (again) and then I tried using some set track as a template for the harder parts:

And it came out quite well. Although its a little tight in set track terms so I softened the radius slightly and he flexi looks ok:

Took me a couple of hours hacking about with the Dremel etc but got this junction tacked down ok:

It then occurred to me that I could do bit of a cheat & use set track on what I plan to be hidden sections. I got some of the transition Peco track sections and nailed them into my first area of concealed running:

So after a full evenings effort:

Today I am planning on starting to build an incline which will be concealed - then appear on the other side of the layout. I can't get the scale of the incline right in the space so i'd rather hide it an have the high level track just appear from a tunnel mouth. So it will run hidden on the thing area of baseboard against the rubbish looking wall. That way I can hide the wall, the set track & the incline. Work in progress....

OO in the loft. Lenz 90 making it go.