Eleanor picked out the yarn and MC, but I get to pick which colour to assign to each other letter on the chart ;)
So:

A - Grey (Silver Cloud 434)
B - Yellow (Tana 390)
C - Teal (633)
D - Cream (411)
E - Green (Kensington Gardens 617)
F - Purple (Purple Sage 615)
G - Orange (Amber 394)

This yarn is only 30% wool but feels ‘woolier’ than that.
Also the label says it can even go in the dryer! So that’s good then, also it means it would be a great yarn for making gifts for non-knitters.

Because I was making a sample I followed the pattern. I usually do colourwork in the round wherever possible, but there was shaping so I just knit it in pieces as the pattern said. That means loads of ends because although the colours are repeated, it is knit flat and they start and end at different sides (why would anyone design it like that?) ggggrrrrrrr ;)

Also, on the copy I am using the chart has mistakes towards the top. Check rows 58, 64 & 72 and make sure the spacing is the same as in the pattern repeats below.
Plus a dot is missing at the beginning of row 68 on mine.

3 colours are used in a row every 18 rows. I’d not done this before, but it was surprisingly manageable. I won’t let it put me off things in the future.

I bound off all the neck and arm ribbing with a 3.75mm needle so it wasn’t too tight.

It’s still drying and I don’t think I’ll get time later, so all pics are pre-blocking (even the first one - it knitted up pretty evenly).

So - although I may use this yarn in the future, I wouldn’t use this pattern again without modifying it to knit in the round and have less ends; but the result is a really cute vest.
So, if you don’t mind sewing in ends (around 225, but hey who’s counting) - then this is the pattern for you ;)