Thank you everybody for your advice regarding this picture - to say it was interesting to see so many different views about cropping the image. I have tried cropping off the bottom as suggested to the first 'black line' and I was not happy with it. Whilst it assisted the thirds principle it seemed to detrimentally affect the balance I was attempting to create - so, so difficult! Thanks for the advice about taking the shot lower - had not thought of that!
Thank you for your generous comments. I look forward to submitting other work.
bobculshaw