These links are very useful and are highly recommended:
The Old Lawnmower Club:
Website: http://www.oldlawnmowerclub.co.uk/
Email: olc@oldlawnmowerclub.co.uk
The Vintage Horticultural Machinery Club:
Website: www.vhgmc.co.uk
For Howard rotovator machine parts, contact:
Chester Hudson
Website: Tiller Parts
Telephone: 07836210363
Clifford Specialist, contact:
Paul Coles
Email: cliffordregister@gmail.com