Thanks, chaps, much appreciated.
how about a few cables here and there?
I am considering that option but will probably do the whole lot at once when they are all done (this is building number four with at least another four buildings plus the railway to do yet!).
One of the constraints that I have is that they will all fit inside each other in various ways for more compact storage, so I cannot have too many fragile bits poking out, but a few cables in protected places are certainly on the 'to-do' list.
The other thing is that, when I have them all done, I can chuck all the remaining small bits in various places on their bases to add interesting features.
Anyways, the thing is now finished so I shall take a few proper pictures later for your perusal.