Where can i get basic training for lawnmower maintenance in gloucestershire?

My old alko petrol mower has cost me the best part of £200 in the last two years on servicing and repairs. It's always simple things but I don't have the knowledge to repair/sevice it myself. I've also got a petrol strimmer. I'd like to do this myself but can't find anywhere local to get the appropriate training. Does anyone have any knowledge on this? Thanks.