Moving light stops, flashes

A single point of white light, the same size (apparently) as the surrounding stars, was moving in a straight line, northward. It had passed overhead (well above the Plough), when it stopped and flashed brightly. Immediately and for about two seconds, it was replaced by a very wide arc of brilliant light.
A week or two prior to this I had seen in the south, at around midnight and probably at about 45 degrees, a single point of light moving from west to east. It flashed 3 times before dipping in a curve and disappearing.
On both occasions the sky was cloudless and there was no noise. I am a middle aged male with an engineering background.
((
An Iridium flare was visible at 21:58 hrs., but it would have been in the ENE and 45 degrees elevation.  Hence, this reported sighting could not have been caused by an Iridium flash.  Please see the following URL for confirmation:  
http://heavens-above.com/iridium.asp?lat=50.388&lng=-4.146&alt=48&loc=Plymouth&TZ=GMT&Date=37495.5733333333&Dur=2
Witness elects to remain totally anonymous.  PD))