The tyre is about a year old. I've lost confidence in the rear and bought a new PR3. Wear on the right hand side is greater than the left which may have contributed.
Uneven wear is pretty common, primarily due to road camber apparently.
Fair call on the replacement. Nothing worse than a lack of faith in yer rubber.
I will see if I can get a pic of the mighty GG hurling me off Jono49. LOL.