After contemplating the track plan a little more using points i had to hand, I've now come to a final decision.
It's still going to be the 4 sidings as before, but laid out not so straight and parallel as the last incarnation.

Peco SL-89 leading to SL-96 and SL-95


Undecided if I should swap the SL-89 for SL-87 curved left hand?
the test board is just in the pictures as an aid to track spacing.
After the pictures were taken the ply was cut roughly in half along it's length so now I can see just how much room I have to play around with.
the 2 half widths of this board will now by joined end to end to double the length.
the plan is now to have a building next to the PWAs for storage, the other 3 sidings being for general use.
So now i have 99% worked out this end, i can start on planning the other
just need to see what other points i have lying around first.