Try the British lawnmower Museum in Southport
http://en.wikipedia.org/wiki/British_Lawnmower_Museum
http://www.lawnmowerworld.co.uk/
Send them an e-mail - or 'phone them
You may notice this site is called How to Mend It...
I hope your neighbour appreciates all the trouble you're going to on his behalf.
Peccavi, May 2013