So as I progressed to wiring up the layout in its test state, I attempted to wire it as a DCC ready layout, only to find that nothing worked.  The loco attempted to crawl along at a snails pace, but something wasn't right and I thought I had a current problem, given that I'm using an old H&M flyer for power at the moment.  I removed all of the droppers and started again with just three.  I'm using insulfrog points so I wired each end of the loop, and the two points that are toe-to-toe at the back of the loop.  Testing again didn't go so well, in fact it didn't go at all so I connected my test leads to an isolated piece of track to re-test the loco.  Sure enough it worked perfectly fine, one end of the layout to the other, so started the process of elimination to discover the problem.  Turns out the Kadee coupler height checker gauge that I had left at one end of the layout was causing a short, removed that and hey presto!

So we have a running layout.  However, as you can see int he photo, there is one less spur at the front left.  I wasn't happy with this spurs location and purpose at it was only there to use a leftover point and represent an eventual industry that I hope will sit at the end of the L-piece.  However, the long term intention is to turn this into a U and the track for that industry will likely run off of the spur to the triangular building at the left end, this building then representing a former rail served industry on a now abandoned spur.  So in short, I removed one more spur and I am very happy with the result, the track plan looksmore like a railroad in a space than a model railroad filling up space.