Tu Chan go, you might have thought some of the answers were less than useful but take our word for it, doing without and using estimation and metal DR helps sharpen your skills and prevents mechanical, or electronic assisted, boo boos.
The actual link you need is this one:
London Name Plate
and then email them at
[email protected].
One item is the 'strike rule' another is the 'Buccaneer Protractor'. Unlike the Douglas it is a substantial piece of kit complete with range scales and rotating azimuth ring. Much better for the short sighted.