I would agree that I'm perplexed by how much Seasalt is derided on MN. Ethically, they rate very highly, as well as being a UK brand. Maybe it's because they're everywhere - but then so are M&S/Monsoon/Next etc ...
I think it's partly because they stock a lot of above-the-knee tunic dresses - the jersey kind worn with leggings - plus cropped trousers (both of which seem to be seen as a last resort from comments I've seen on MN). Also, their floral patterns in particular can be quite dated, while also distinctive (although they sometimes get patterns, especially checks or abstracts, really spot on). Their knitwear is pretty good (in particular the men's jumpers).
Both the check dresses linked are really nice colourways, & I like their linen dresses too. They're not exciting - but they do come in some lovely colours & simple cuts, & would be easy to style with the right footwear & other accessories to look contemporary (& not instantly identifiable as Seasalt, if that's a factor).
For instance, this really plainly cut mauve one is a bit dull on its own - but is a great colour on the model, & with the shades, chocolate suede sandals & a striped raffia bag it all comes together as a cool- & relaxed-looking outfit with minimal effort. Nothing ground-breaking - but a lot better than some of the polyester mesh frocks suggested on here for summer wear!!!
However, what frustrates me personally about Seasalt is that even their regular length in dresses & skirts is too short - I look like I've had a growth spurt in their clothing! I wish they'd do them in tall! (I think your Palava dresses also look perfect for more petite women, but the length & cut are wrong for me.)