England (Including Isle of Man, Channel Islands, Scilly etc)
Aberfal Outdoor Pursuits, (gylly Advenetures) 3 sites in Cornwall, offer kayak, SOT and wetsuit hire.
Active4seasons are based in North Northumberland and offer a range of outdoor activities, including sea kayaking.
Adventurous Experiences - based on the Isle of Man, they say they specialise in sea kayaking as well as other outdoor activity.
Jersey Sea Kayak Adventures offer paddling on Jersey.
Kim Bull offers coaching and sea kayaking trips in Northumberland and the North East.
Sea Kayaking Cornwall is an expedition centre specializing in sea kayak tuition and expedition training. Run by Jeff Allen and Simon Osbourne.
Woodmill Canoe Shop and Activities Centre - based in Swaythling, at the head of the tidal River Itchen, they hire sea kayaks and a variety of other craft.