Just picked up this "variation" , post 1987 (?) but with no enamel.
This badge has been discussed before and the options were :
1. A 'variation' or specially produced badge.
2. A 'modified' badge that has had enamel removed (either damaged or to appear "rare").
3. A production/manufacturing error (enamel never applied).
Now that I have one to hand , I don't think the enamel has been deliberately removed. Too much work for a "common" badge and no one is asking high prices for them.
My first thought was manufacturing error but I would have assumed that the lion head is attached/glued on after the enamelling process , so badge would have failed quality assurance check.
It is possible it could be a prototype/trial 'variation' as there are some RBL badges/medals which have 'plain metal' and enamelled types available.
Any opinions ?
.