Sarah - Thanks so much for chiming in. I'm adding Oboz to the brands I want to check out.
JAileen - Ah sorry, you mentioned the brand in your first comment! I've had a look around the Muck and Xtratuf websites, and really like what I'm seeing (so many fun linings on the Xtratuf indeed). Thanks for adding the photos, if your Muck boots could stand up to that kind of mud and work on three Alaska trips, then they will definitely work for the Belgian seaside
Suz - Awww thank you (I think so too, but I'm biased, of course ,-) Good to hear your Sorels are lightweight. And I think I have a wider heel than you, so probably won't have that problem.
- Staysfit - Yes, I think you are right about high tops. I've done some short beach walks this Summer with low-top sneakers, and the sand got in very easily. OK, Asolo is going on my list too Thanks!
And again, thanks so much everyone for all these wonderful tips and suggestions. You are a fount of wisdom! I'm learning about so many new-to-me brands, and they all sound amazing. I wish all of them were available here, I’d love to try them all on. Now that I have orthotics it’s tricky to order online, especially from abroad as it’s expensive to return shouldn’t they work out. But I've been able to find some of the brands mentioned in this thread on Zalando (big online European store), and have several on order.