[BNM] Beginners RSS Feed

[Chris Adams]

Hello all,
I'm dipping my toes into RSS, creating a very basic xml feed for the 
home page of a site, linking to this from an rss icon on the home page, 
which is then adding the feed to my reader of choice (Google Reader) 
successfully.
However when I then UPDATE the page and feed (manually using textpad) 
and ftp these changes up, Google Reader doesn't update my listings to 
show that the content has been refreshed....
For anyone interested in looking go to 
http://www.fiubonacci-designs.co.uk/ to see the feed icon & subscribe.
Do I need to submit the feed to a directory to get this working, 
register it with search engines or add different elements to the xml 
file etc?
I am sure that I am missing a very significant trick here, and would 
greatly appreciate any help to get me off on the right foot.
Many thanks for looking,
Chris