The RS part - Schaffner FN372-2-21 - is a little over £20 from Mouser in the UK and a little over £15 in the USA
http://www.onlinecomponents.com/scha...tml?p=12332112. However the US seller has a $100 international minimum order so you'd need to find someone in the US who was prepared to buy it for you.
Cheers,
GJ