Hi Robin, long time....
I believe you need 13mm dovetail mounts, not as popular as the standard 11mm (3/8").
Sportsmatch make them: https://www.ant-supplies.uk/scope-ri...ope-rings.html
Also in the old days you were able to 'reverse' the mounting feet on the Sportsmatch and that made the standard 11mm into 13mm, not sure if that is the case, as I mostly use BKL these days...