Oh, don't worry about the helmets. Take this example:

http://www.northyorkmoors.org.uk/vis...d-sea-kayaking

That area is great (I'm no good at sea kayaking, mind, so can't specifically advise). Flamborough Head is another popular spot. It's a sport in relative infancy here. There's a couple of groups you might want to get in touch with:

https://www.facebook.com/groups/593402984102669/

You may also want to consider Northumberland - a hugely underrated county with a beautiful coastline:

http://www.seakayakingnorthumberland.co.uk/index.html