Concert Pitch is the wrong way round

Hello, I am using a Windows 11 64-bit Home Edition

I am using musescore 4.3.3 and have been using musescore for years but seem to have come across an odd problem.

I have arranged a piece for British Brass Band using the templates I always do, therefore, Eb instruments (soprano cornet, horns and Eb Bass) should be in a different key to all the other Bb instruments.

In short, when I click 'Concert Pitch', it shows the Bb instruments in Eb Major and the Eb Instruments in Ab major. When I De-select 'Concert Pitch' all instruments are in F Major.

This should be the other way round and I'm not sure what I've done to make this happen so would appreciate help.

I have attached the score below.