BSA Martini International ‘Scope brackets.
I designed these brackets for the MkI and MkII with the 1-1/8″ receiver width however they also work with the MkIII/MkIV/MkV 1-1/16″ receiver albeit with the central axis of the rail shifted by a 1/16″ which is 1.58mm. I doubt you will notice the change once zeroed if it is to be used at a fixed distance such as 25 yards/metres. The finish is satin black Anodised finish and they do look nice on the Internationals.
If anyone is interested in just how much of an issue the misalignment of just under 1,6mm is at 25m I will take my socks off and have a go at the math, I might just do it anyway to satisfy my own curiosity.
EDIT - I reckon the variance of 1,58mm scope offset is the equivalent to 0.0054 MOA calculated at 100 metres and I have checked my calculations twice with the same result however it was a Monday and I was yet to start my second coffee of the day…