I know tonnes of people including myself are in dire need of these parts, and just found on a puma repair facebook page that i am on that this company now supply these parts at a very reasonable price, i am in no way affiliated, just passing on the news....
http://www.steelpanels.co.uk/news/ford-puma-sills/
http://www.steelpanels.co.uk/news/ford-puma-sills/