I think I've worked out what I did wrong the first time around. On row 12 of chart A I did the yarn over at the start of the next needle instead of at the end of the needle it was supposed to go on. This put everything out of whack. I'm optimistic that I might just get a bit further this time although I'm yet to get to the end of Chart A for the first repeat.
The yarn is lovely. I'm using 2 strands of Marta's Yarns 2 ply wool. One is a pale greyish green, the other is a multi in sort of camouflage colours. I'm enjoying the yarn so much that on the weekend I went to Marta's and lashed out on some more 2 ply in other colours to make myself (gasp!) some more socks. I'm starting to understand the stash problems of other knit-bloggers.