Suggestions needed choosing yarn for a blanket

[PaperPanama]

I am going to crochet a sofa blanket for my son's housewarming. He'd like shades of green from medium to dark, and a contrasting creamy white. I haven't decided on a pattern - he's leaving that to me.

Please suggest yarns. I'm not massively keen on Stylecraft Special DK. It's OK, but stretchy and heavy, and it does eventually bobble. Perhaps something a little nicer, with a percentage of natural fibres? And available in the UK. Any ideas?

Yarnsmiths Merino DK is affordable (Wool Warehouse) and comes in lots of colours, it is quite soft and crochets nicely. I did a group project blanket in it recently and everybody liked working with it. Or Cascade 220 superwash, same retailer, slightly heavier yarn?

I quite like Scheepjes SoftFun, it's a cotton/acrylic blend, has a massive colour range, and is lovely to work with. It doesn't pill and has a nice sturdiness while still feeling soft. Plus easy to wash and dry.