Just called my LBS.
They phoned Madison for me to confirm.
However they said Madison won't pay their labour charge or postage. The LBS need to charge me £20 labour and £10 postage to sort it out for me.
soooo.....
Madison will only deal with a bike shop, and the bike shop have to charge me for their costs (I understand of course the LBS shouldn't be out of pocket).
The cost amount to double that of just buying a new (rubbish) chainset.
GRRR what a stupid situation.