Paul,

For the most detail on St Ives tides, just before you go away go to
http://easytide.ukho.gov.uk/easytide...ide/index.aspx, select free
predictions, then St Ives.

You only get 7 days but there is a lot of detail. Heights of Low & High
water above chart datum, time to the nearest minute, and the inevitable
graph.

Graham
Penzance