redsaw, soz but your information isnt correct,
i served my apprentiship in spain, (20 years ago) my paperwork that says im a plumber in spanish isnt recognized here.
you can sit your acs gas assesments as a cat 2. all you have to do is build a portfolio of 30 or so pics of you working on gas supervised by a gas safe registered plumber who can sign your work off, you then use this as evidence. you can then sit the exams. (with extra training if you wish)
cat 3 students are peps with no previous plumbing or gas experience who have a lot of work to do.
cat 1 students. just topping up or repeating.
shaun