Part 2 adds a 'full' indicator, at the moment the indicator is not bistable, and it does not switch off the charger. Ideally we actually want the trickle-charge step to trip in and out, a little hysteresis should do the trick. Here is the final diagram. (right-click and view image separately to zoom in)
Since I have not got the enclosure I ordered, (which will go under this bit) that's another reason this project is not yet closed off.
You should just be able to see the battery pack connections on the pack (top of shot) and base, I have re-built the connections with some small pieces of un-etched PCB.