OK, found some time today to have a play with the timing, set at 12* initial & around 34* total. Just curious, should the idle speed increase when I reconnect the vac advance after timing, & does this mean I have vac advance already at idle ?
Also removed thermostat housing for a look & lo & behold, no thermostat fitted. I'm thinking my warmer temp at highway speed is possibly because the coolant was flowing too quickly through the radiator. Bought a hi-volume 170* t/stat, & flushed & replaced all the coolant. Going on a cruise on Sunday, so fingers crossed, will see how it goes.