I found the valve I was after for an MFI toilet from Siamp (based in manchester) via the cisternspares link above. I know this is an old post but thought this bit of info would be useful for others also.
Mark, April 2011
Try www.cisternspares.co.uk
Andrew, May 2008
Look up in directory local plubming shops [if you haven't tried already] ring and ask them. I assume MFI was as useful as a chocolate tea pot.
Charlie, April 2008
edit
I can answer this question...
Where can i get a float valve washer for mfi danube toilet?