Just noticed in this week's MCN that they have a Draper Spindle Key on offer. From experience they work much better than a filed down piece of wood.
http://shop.motorcyclenews.com/product/340/draper-expert-spindle-key
£12.29 + P&P
http://shop.motorcyclenews.com/product/340/draper-expert-spindle-key
£12.29 + P&P