At the moment, I can do 80 5kg bicep curls before failure, which is pretty good, and I feel I'm getting nothing for it."
Too many,Fluff. You would be firming up and increasing stamina but actually LOSING bulk. No more than 10 of anything, mate....and do the same sets only every second day to allow muscle to repair... We used to take Creatine Syrup, but then they took it off the market for some reason... If I was you I'd get a workout plan designed by a professional to avoid wasting time & effort. My first foray into weights (in 1970's) gave no results at all until someone pointed out my errors.....the literally hundreds of pushups, situps, squats, chinups I did daily undid the affect of the weights.....the repetition, see. Good luck.
