scrappy near us has several, Infact one is from a sei that hasn't done many miles, just took a severe bash up the bum (in a none sexy way!) i'm more than willing to take one off for you if you pay for the cost of the part and postage/courier?
they (windleys) want 40 quid plus vat for a head with no rocker gear. i rang them today. the first quote was for 80 quid with rocker gear and any other bits attached to it. these quotes are for self removal too!
I found several in a wee Fiat breakers just outside York today, £40, removed. When the customer was phoned he couldn't make his mind up so it was left.