At first look it could very well be Charlies bike, twin front down tubes and early Hagon seat.
In 1971 a guy on a Maico won the 250 & 350 ( Lightweight & Junior ) Aussie titles and Charlie the 125 (Ultra-lightweight ).
Please excuse my ignorance on Bultaco models but I assume the ElBandido is a 125?
Ian should chime in soon as to whether it's a Hagon or a copy.
I'm interested.