I only use 'hold back' (right arm extended at 45 degrees, palm facing back, fingers spread, very.emphatic.gesture.) when riding at the back of a group, along with lots of rear obvs. used in on Sunday morning. Nobber tried the overtake anyway. Horsebox came round the corner and nobber tried to kill three of us.
As to signalling when passing parked cars? Flip no. Lots of very.obvious.repeated.rear.obvs.though. Following driver won't be looking at me anyway and will miss the signal. If they are looking at me they'll figure out I'm unlike to pop a manual and mount the boot of the parked car.
I also do the looking back, but some drivers when they see a gap on the left think that for some reason I am going to swerve into it to let them past, so I have to be extra obvious that I won't be moving across... I have got to the point now, especially in this weather, where I have to treat everyone on the road as being completely stupid and incapable of driving properly...
This traffic island is interesting at night (
http://goo.gl/maps/7qFyf ), as you get cars parked in all the parking space both before and after it.
When you get near the end of the row of parked cars some drivers seem to think you will be moving back to the left, so I have to show clearly that I will be maintaining primary as I will very quickly be coming up to the traffic island (pinch point) and beyond that more parked cars.
I have found if you don't make the obvious, well "obvious", then you will get some idiot who will do something stupid, all to gain one car space at the next lights... where you will most likely end up filtering past them again, gaining them zero time...
Of course, not all drivers are like that, but bringing it down to the level of the poorest skilled driver seems to be the way to go...
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