Hi mate, im in similar boat!!
was originally a mechanic on a nuke Sub for the navy with very little electrical experience until i got a 440v shock from incompetent workmanship by a collegue!!
i learnt what i could from books, courses, passed 17th edition, PAT testing, did a distance learning level 3 Electrical Diploma with BTEC 18month (similar to the 2330 but not as expensive) and currently in final phases of my NVQ 3 , in mean time started to take more interest in electrics at work lighting , distribution etc etc... passed the 2391 first time and did some work for a domestic company!! let lose on first day (scary) but as i was use to 3 phase crazy stuff single phase was easy as cake..!! found my feet very quickly but still bit behind on the calculations and methods! i.e cable pulling, ratings etc but thats what the OSG is for..!.!! and im sure that will natural come as time passes on!!
buy yes i was scared and yes i do still ask questions!!!! rather take time than have to return to carry out extra works due to oversights.. (dont look good)
plus i know im still 100% better than the cowboys out there!!
steve