I think, Neil, that I would try cropping just a fraction closer and lose part of the bottom and right side. You should be able to get something around 4 x 5 ratio.
It may take a tiny bit extra brightness on the highlights. But I suspect this is a case of try it then decide.
Hi Neil, I like what you have done here. The thing is that this lady has intriguing eyes so I would also crop it to bring them out. It would be good to see a tight crop to see what it looks like. Nice work.