Do a search on Utube, there are quite a few instruction videos on how to rewind it step by step and safely, it even shows how to repair a broken spring if it is just the hook that's broken.
For safetys sake wear eye protection when dealing with coiled springs.
If you'r not confident at tackling the job then £20.00
inc P&P seems like a fair offer,or you could look out for a secondhand machine for spares or repair on an auction site.
You just need to undo the four retaining bolts to lift off the unit, ( nothing will spring out at this stage ) then bolt on the new unit, or attempt the repair folowing the instructions given on Utube.
Good luck.
Stan B.
May 2010
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix lawn mowers.