Dunnock. (Prunella modularis)
When I was a lad we called Dunnocks "Blue Dykies" but the bird books called the Hedge Sparrows. Apart from the fact they aren't Sparrows it is a singularly appropriate name.
They prefer spending time on the ground or under deep cover. Hedges provided good cover to pop out from occasionally and being a low level/ground nester they are ideal habitat. Normally the only time a Dunnock os stationary for more than a few seconds and in clear view is when the male is "song posting" to mark his territory.
One of our resident pair does sometimes venture 1.3 m (4 ft) off the ground to see what is in the seed feeding tray.Still very waryas the stance suggests it is still long enough for a blip.