I'm quite close to the sea too & dont have any problems with herbs. Rosemary is doing nicely, parsley & thyme ok, also have chives, lemon sorrel, lemon balm, basil. I've just bought feverfew & oregano which are still in their pots but surviving. Give them a bit of shelter if on a windy site & dont feed them too much, I've heard poor soil is better. Good luck.