There is a link at the bottom of the page for Kit. There are other useful links, all of which are recommended reading.
Could I emphasize ......
Dry suits only - in summer it might be possible to manage without a dry suit, but in winter an early dip has more severe consequences for the individual concerned and can spoil the day for the rest of the group.
Kayak specific helmets with protection over temples and ears must be worn on theses trips. Something like a Sweet Rocker as oppose to a Sweet Strutter - other brands are available