There is a slope from the bottom of the garden to the top and also from side to side
I did contact the manufacture's technical department and they gave me some things to look at, I mentioned tem to the guy who serviced it and he was already aware of the advice. He suggested the guy who had the house before me used the mower on the steeper part of the garden (I leave that section to grow wild) and thinks it may have impacted the gears. I have queried this with the manufacturer as I think it is only 4 years old and for the last 2 years I have not used it on the steeper part of the garden.
How long are these things meant to last?