Thanks Mowerfreak, paul_c and NormK.
I found the fact that someone wouldn't want to know what fuel mix their mower used very strange - then I put 2 and 2 together and it came straight up on gumtree.
Hopefully whomever buys it will look after it properly

Thanks for your support, I was a little bit apprehensive about posting the comment, but I now see I needn't have been worried

Regards
Tyler