Ok, my stuff arrived (impressively fast) so here's my feedback.
Sizing is too inconsistent for online sales. Sizes of trousers varied wildly. Also dresses in 18 are big on me, especially around hips. Whereas trousers often a bit small, especially around hips. Well, bum.
Cotton Twill Side Button Trousers - these are special. Old-fashioned-quality fabric and cut. Gorgeous flattering fit around curvy hips, bottom, tummy. The 18 is plenty big enough on me, which means it's a very very generous 18. But they needed to be more tapered to be really beautiful, imo. They look best with a turn-up, but they're already short (I'm 5'7", 172 cm so average for my generation), so that's a bit annoying. I get that Toast is about an unconventional cut etc etc, but I still feel like the designers could spend a bit more time looking at what actually looks nice. Anyway, they're keepers.
Garment Dyed Linen Pull On Trousers (Black coffee) - these look like I got them at Sainsburys. Without any great disrespect to Sainsburys - I'd have been very pleased to find these there. But not at Toast prices. Fabric and colour depressing. Small on bottom, not flattering. Very meh.
Cord Tapered Trousers - too balloony on me, though I gather from reviews that this improves with washing. Too expensive to take the risk, I felt. Actually I reckon they'd have looked ok if I were half a dress size less fat, but not keeping to see. Lovely colour (brown slate) and fabric. Feel and look like the quality you'd expect. Easy to move in. Love these trouser styles that are actually comfy to wear.
Felix Indigo Denim Trousers - really like these. Again I'd wish for just a bit more taper to make the legs feel as well-designed as the upper parts. They come up smaller than the Cotton Twill Side Button Trousers; I need to lose a few more kilos before they'll really work. Keeping since I'm shrinking fairly successfully atm and these will be a nice reward. The denim feels gorgeous. Quite light, will be a good spring/summer trouser.