Jeckells are a UK based outfit from my neck of the woods. They originated doing sails for the yachts of the Broads - an extensive and popular area of rivers and lakes in the UK, although now they do a lot of sea going stuff as well.
It's a family owned company, and they race passionately. Locally nobody buys anything else, and as this includes the North Sea - arguably one of the worst tempered and most treacherous pieces water of water in the world.
My personal experience with their sails was on a 40' cat sailing the North Sea and some of the Dutch inland waterways. We got caught in a force 8 on the way back, and the reefing lines gave way due to being too thin. Having said this, the full sail we were then left with performed fantastically, and survived this battering without a mark.