Have you given ZMA a go, boz?
Been taking them for the last couple of weeks and although I don't notice a significant change like hey presto (unlike melatonin, which was immediately noticeable, whether good or bad effects), since taking the ZMA I seem to be able to last better in the day on insomniac sleep. May have helped with muscle recovery too? Dunno. Will have to test further by hopping off it for a few weeks and then back on. I tend to notice the effects of stimuli more in withdrawal than adding.
So many factors affecting performance at the gym; you can seldom reliably test the effects of something on your performance over short term or even long term use. Really need big sampled studies, but even then, you may be one of the people who don't respond to something lol