Thanks for the replies.
The most recent one I'm trying to fit is non-magnetic (so assume it's stainless). I don't know if it is a MS supply. Will look into trying another source.

I'm just about at paint stage and tried to fit the moustache to the front of the car.

No chance, not even close.....

It wasn't on the car when I bought it and I'm now concerned that a bad repair may be the issue.

Is there a possibility that the front end is of a later model or similar or is it just the old crusty metal moustache is way out?

The pressed grill fits fine. the bonnet doesn't line up all that well but I'm guessing that's normal.

Any suggestions welcome.

I went through about 7 used ones that were borrowed from a friend - only 1 was close but dinged and needed rechroming. I had fitted a new front panel years ago and am sure it was a genuine part. When I went to get that moustache rechromed, they said it was too thin take linishing to a smooth surface for plating. So bought a new one from the same place I bought the front panel from but it didn't fit.
Also thought the new panel might have been for a Mk2 UK model and was different from Mk1 UK. The moustache on the car now is from Minispares who say their bar should fit all model minis including Mk2 getting the retro look to be Mk1, which means it should fit mine IF the panel was from UK.
Altogether I have bought 3 new moustaches, so it's been a long, expensive effort and still only fits where it touches and it exposes some holes in the panel that should be covered (in photo).
I think the original moustaches were made in the Sydney factory (like all the stainless trim) to fit Oz minis. Now the moustaches are to suit mostly UK models. There shouldn't be a difference but there are many other slight differences in panels.
I made this moustache fit by using long self tapping screws and gradually pulling the moustache up to best fit. Most of the screws are not a tight fit. They all vary. To get the ends of the moustache to line up with the little whiskers meant there is a gap along the top.
And I had to repaint the panel again after all the trial fittings.

By "wider shots" do you mean the top of the slam panel where the moustache meets/covers the edge of the slam panel?

The blue car has the poorly fitting moustache. The top of it does not reach the top of the slam panel.
Also a shot of my white Mk2 - all original parts. Note the moustache just reaches the edge of the slam panel but not over it, which later reproductions often did.