Hi again 

Replacing the chain & sprockets on the evo it's currently running 11-41 combo which i dont think is standard. New to trials so would I be OK sticking with this or is there a better combo for a total novice. I'm just going with a did or afam gold 520 non o ring chain.

I would keep it standard.  The different models have different sprokets so check to see if yours is modified.  I replaced them on the missus 250 - 11 front (9 on 125) 41 rear.  There is a chart on splatshop - https://www.splatshop.co.uk/talon-rear-sprockets.html

Running 10/42 on my 2019 Beta 200. Feels perfect to me but could see using 10/43. I purchased my bike used and he had 9/42 which was too low, for me, I ran out of gear. I guess shift up but I was used to using a certain gear in a certain situation.