After a lot of head scratching I very recently raided the savings and upgraded my cheaper Cannon 70-300mm 'kit' lens to the EF70-300mm f4-5.6L IS USM lens and tested it out during a very brief walk at Witley Common.
Stonechat (Saxicola torquatus). Above is the original shot taken hand-held as usual and below is a more detailed crop.
So am I pleased with the performance so far ..... definitely yes. FAB.