Qualification badges on No.2 dress

Can anybody confirm the correct place for a qualification badge on number 2 dress, namely the crossed flag signals instructor badge?
On remembrance parade recently I saw 3 variations. One was a single badge on the right forearm, another was a badge on each forearm, and the other was worn above the rank chevrons on the right arm.

 

Sig class 3 (user) no flag, sig class 2 - flag left forearm, sig class 1 right forearm, RSI above rank right arm

 

So it's not just a straight forward 'you're a signals instructor and this is the badge you wear' then? I didn't realise there were different levels to being a signals instructor. I thought it was all one course although I can understand there being an RSI who I presume is responsible for disseminating information to all the the other signals instructors in the unit.

 

Different Regiments different rules

In the RA a basic Signaller (class 2) would wear them on lower left cuff, Advanced (class 1) lower right cuff and Det Commander above rank

We used to have a rule in my regt that only approved Instructors could wear flags on jumpers, to be an instructor you needed to do the DC course as well as the instructors. but they were run together so almost all Dcs were instructors (less those who failed that part)