Just an FYI, very nice insignia btw, Sergant Major is no longer a rank in the British Army.
The Insignia you have for Sergant Major is a Warrant Officer 2nd Class, and Regiment Serg Maj, is a Warrant Officer 1st Class.
Also, Colour Sergant is for infantry regiments, since they held the colour. Staff Sergant is the rank for other corps, like the Armoured Corps for example, and an alternative badge, with the same insignia, different title, would be nice
Apart from that, very nice insignia, I'll be using these on my sigs and stuff
btw: I know what I'm talking about, I'm a 2nd lieutenant