Just had a look through my 6859:
Nav Inst Mechanic
Flight Systems Mechanic
Flight Systems Technician
Engineering Technician Avionics
More or less the same job with four name changes. Makes me sound windswept and interesting I suppose. I'm guessing that putting 'Engineering' in front of 'Technician' was a bit of sales blather to flog it to new recruits. Sounds a bit more rarified than just plain old technician. I guess it's in line with 'upping' the spec of fairly banal jobs society wide. Refuse disposal officers and barista spring to mind. Not that I found being a techy banal by the way.
I've also found that I was awarded the X717 annotation of Instrument Maker and Horological Skills on 20 Feb '84. Bet that's a rare bird, can't even remember getting it.