Thanks John, I really appreciate your taking the time to help with this. I was thinking the same thing, ie to start with the signals on the platform ends, and yes I am intending to use colour light signals. Would these just be 3 aspect signals to indicate a clear route ahead? To be honest I haven't even determined which are the up/down lines - it depends in which directions trains run best, there's a particularly troublesome set of points on the inner circuit which is OK as a trailing point but not facing, causes derailments for some reason, so I guess that determines it's the down line, although it really should be up, just because the real location this fictional layout is based on is lodged so firmly in my head, if that makes any sense.... thought not.
http://www.expressmodels.co.uk/acata...s_Signals.html
It's the Wigan show next week so I'll probably pick some up from there. The next challenge will be wiring them... not my strong point. Thanks again, I'll report back.