Thanks guys

Good one. Have you tried a green filter? That is, if there any greens at all in the subject.
Yes that could probably work Paulo, but the main reason I took this image as a black and white, is because I was using my old and now comparatively very cheap 16-35 L Mk1 lens close in for the detail, which is a lens I had almost completely stopped using, as the CA it created with my old Canon camera was horrendous and the images were usually too difficult to correct successfully in post. So I was forced to use it as a black and white only lens on the odd occasions that I did take it out with me. But then I bought the A7R2 and the sensor in this camera has totally breathed a whole new life into this old workhorse of a lens, which now appears to be substantially sharper and the CA is both minimal and manageable, yet I still always think black and white when I am using it and for this shot I am so glad that I did.
Dave