"Great Britain Used In Malta"

I have a 1/2d stamp which is described by my imaging software as noted above, specifically Scott No. AP23PL12. Where would I find it in the Scott catalog? For reference it's in the SG catalog as Z23PL12.

i wonder how that software came to that conclusion.

GIGO

To the right, it looks like (GRA)NTHAM to me.

Could be an 'R' and an 'S'. Corsham?

Unlikely. It would be symmetrical in its placement Corsham would be a letter short. But it, surely, is not MALTA.

Edit: AMERSHAM would fit better than CORSHAM, if, indeed, it is "RSHAM."

Software ID photos added ...

See photos added above, may have to be deleted ...

A yes, I think I know what app you used. It got it wrong.

The screenshot shows a typical Maltese cancellation with "MALTA" in a straight line over the date. The stamp in the OP does not have a Maltese cancellation. It is an ordinary bantam with a UK, most likely English cancellation.

Z23 is a halfpenny used in Malta, PL12 is a plate 12 example of the bantam. So Z23PL12, is a halfpenny (bantam) from plate 12, used in Malta.

Your stamp is not Malta Z23. I cannot even confirm the plate number.

NSK, so is it regular Great Britain? What year, please, thanks,

It is SG48 or 49, depending on the colour (rose-red or rose), specialised G4(1) or G4(2), respectively.

Issued 1-10-1870 but it depends on the plate number. These were issued until 1879 H2.

Thanks!

Yes, Amersham would fit better.

A slightly longer candidate would be CAVERSHAM.