Thanks for the replies, even Mcrews who raises a titter
@CFG - Thanks for the link, I read that and it states the 2010 Prius (ours is a 2011 1.8L T-Spirit) is unaffected. I haven't read it all yet though, I will before we go into the dealer and maybe print some bits off.
@3dPlane & bwilson - It will be going to the dealer asap but I'm not sure I can get it to repeat on demand. There isn't anything unusual I can think about in our area - no especially heavy rain or unusual temps or dirt etc. Our area is typical UK "green and pleasant land" if you know what I mean and the car lives on tarmac and solid ground - no dirt or grass.
@all I checked with Mrs A this morning and she hasn't had it happen to her at all and thinks I need new pills
- or is convinced I activated cruise by mistake which I'm sure I didn't - no speedo with the arrow symbol light on the dash.
Could it be the technique I was using ? I had it in Eco mode and was accelerating firmly but not dragster style to the PSL (30) and then lifting off so that the Hybrid system shut off the engine and we would coast. When I lifted the pedal didn't come up so its more a physical thing, although cruise does hold the pedal position? I did this probably 50-100 times during my couple of hours drive and it only happened twice. The pedal hasn't been sticky or stiff, but I do find it stiffer than my Aygo's which is a traditional cable type.
The only correlating factor could be that up until this point before both events I had been parked and then had been travelling slow enough to be running on battery only up to the point I accelerated so this was the first engine start since I had turned the car on again. But again I had stopped 4 or 5 times previously on rattle hunt and it didn't occurr then.
I'll report back what the stealer says when it gets in, this PM.