[GrahamS]

I always calibrate my lenses to my bodies. For those who would like to know how, see here:

https://photographylife.com/how-to-calibrate-lenses

A calibration target does not have to cost the earth - I bought mine from Amazon but this one works just as well:
http://petapixel.com/2013/03/12/ghettoca...led-dslrs/

Here's the Amazon version - the pack comes with two targets:
https://www.amazon.co.uk/DSLRKIT-Focus-C...ation+tool

You will be surprised at the difference it makes!