I would guarantee you would have got a better result if you had used f8 and a decent tripod Mick let alone any micro adjustments, but at the end of the day if you are happy with a shot like this then that is all that matters. All the very best anyway Mick.
I agree about shooting at f8, I wanted to test the lens wide open, once I'm happy with it I'll move away from it when possible. I have a decent tripod and find it too restrictive for birds in flight and only really use it regularly in winter when it's cold or if I'm going to be in one place for any length of time. I only use it when cold so that I can put my hands in my pockets to keep them warm because I'm soft. I've invested in really warm gloves and they do a job while being too clumsy to be a first choice option.