I'm trying to put a name to a movie or TV show that I saw, featuring ritual combat with a 2 handed mace.
It was quite a few years ago since I saw it, so I only have vague recollections. It might have been a Henry the VIII drama.

If anyone has seen this show, how authentic is the mace?

Manouchehr has around twenty Persian maces in his book.One if them is heavy enough to have been two-handed.

Was it Excalibur...they used large 2 handed flanged maces in the duel between Gawain and Lancelot(see video below at approx 0:36)...

https://www.youtube.com/watch?v=AvZS3zzLY9s

There was a Henry VIII series with Ray Winstone where he's using something like a 2 handed double-headed mace in one scene. Really more of a steel staff than a mace.

It wasn't Excalibur despite there being 2 handed flanged maces(I had forgotten that, I do remember those weapons they duelled with a little later though, thick two handed estoc , with vamplate like guards). Love that movie.

I checked the Ray Winstone angle. I believe it was the movie, despite not being able to see it all on you tube. There was one short clip that seems to be at the end of the duel/training exercise, where Winstone is confronted by Sean Bean and his retinue.
Winstone holds a shoulder length staff topped with a closely flanged mace head, which he quickly tosses to the ground.
Thanks for your leads.