Additionally there were RAF apprentices that passed out as JT after 3 years (Dual trade Airframe Engines) and were promoted to CPL after one.....
Similar system as the Army for technicians, but you could be either an apprentice or adult entry. Leave training (12-18mos) as LCpl. Difference in length of training due to specialism, and HGV driving course. Promote Cpl after 1 year and award of class II. Not sure if the RAF had this, but 3 years after being promoted Cpl, attend year-long Class I course. Promote Sgt on completion, 5 years after leaving initial training.
I've looked into the pay rates, but it's all changed with the advent of Pay 2000. Last I could find was the AFPRB report for 2001 when Pay 2000 was introduced.
Office of Manpower Economics - AFPRB reports
Page 48 of the 2001/2 report shows a table of salaries (cross service) but based on Army ranks. There is a footnote under the table indicating that RN & RAF equivalent ranks were used for reference purposes, and where no equivalent rank existed (JT, for example), a formula was used. I would imagine that a JT would get a fixed percentage of another reference point. Say 97% of LCpl or 110% of Private.
I wasn't a LCpl very long (see above), but I do recall comparing pay statements with JTs in the bar, and there was a slight difference (in the Army's favour). We put this down to the NCO aspect of it, and moved on to laughing at RAFP LAC Acting (Unpaid) Cpls.