Strange or Mystery Meteor?!

[sjd63]

Hi,
Long shot question for any vintage BSA afficiando's please!

I just bought a nice old Beeza Meteor, Private sale.
On first glance it looks like a Mk2 , and thats what I assumed from the pics in the advert, but maybe it's a bit of an odd one. Perhaps?

Barrel is Mk2 in design - i.e. the simpler dovetailed blade foresight. and dovetail single-tang rearsight.
Breech block serial is not clear - lettering is not clearly stamped and barrel has been repainted - It's obscured, I cannot make out prefix even under magnifier. But design-wise barrrel absolutely has the exact features of a Mk2.

But itis the Cylinder that is the apparently odd thing.
It has the older 'Mk 1 & 2' style BSA Meteor logo - the chevron design, placed just behind the breech, as opposed to the later and more common 'between the scope' rails block lettering.

But, despite that Mk2 style 'logo' it has the regular shallow Meteor scope rails - standard width.
All the Mk 2's that I have seen have the x4 wider 'gouge' grooves - like the Mk 1.

I realise the rifle could be a bitsa/mongrel, but that doesnt quite explain the cylinder design, which, naturally can only have come from one gun.

I assume it is possibly a transition model, but my curiosity wants to know! - is that cylinder a late, late Mk2 or an early, early Mk3, or ..
Person I bought it off isnt in posession of info regards previous history.

Has anyone seen one similar?