I tend to think of them as a split collet rather than a bullet...size depends on how often they've been used, but they can be pushed open again. The originals were more nicely formed than the modern replicas, as with so many things.

https://www.feked.com/lucas-dynamo-bullet-connectors-brass-bullet-or-split-type-pack-of-6-en.html

Hi Rik,

Many thanks for the reply and the link.

Cheers
Col