Ted,
Thanks for posting the photos of that Halifax. The quality really shows. It's really impressive how much care and craftsmanship the best firms put into even their "low-grade" guns before the wars. That's just one beautiful piece. So great you found one that fits so well!

As Ted has pointed out, the R models have a handy workaround using the cocking lever as a safety. It's as ergonomic as you could wish and much bigger than any conventional safety button. I rarely bother with the push-through safety rod on my R15.
Bill