I had a blazer made up in navy Fox flannel, c. 13oz a couple of years ago and wear it lots.  The flannel is very 'tufty' and textured compared with others I have seen and I works casually and in less formal business settings.  Only drawback with flannel for a blazer is that I don't like to wear it with grey flannel trousers as the two flannels don't work well together, but it's great with khaki/cream trousers and similar.

When I started at grammar school most of the kids blazers were made of a rough hardwearing serge. But the local school outfitters also had the more expensive version made from Barathea, a much smarter and finer cloth that I now realise was a lightweight hopsack. My parents were not wealthy, but Mum went the extra mile, and on my first day proudly sent me off in my new uniform and the premium blazer. Unfortunately the tradition at that school was for new boys to be thrown into a holly bush every lunchtime for the first week, the blazer was not so pristine after that!

Barathea - an excellent cloth for a really smart blazer Goodyear, probably not much chance of anyone throwing you in a spiky bush.

Can we see pics of her prickly bush please

Never had anything in bamboo, does it crease much DH?

I had a jacket in bamboo, can't remember what became of it, but it held-up well to creases as I remember.

That SW4687, 4688, 4691 cloth would look great in trousers with a navy blazer.

I'm a big fan of Smiths, don't think you can go wrong there.

I'd suggest Harrison's Frontier, a 10-ounce hopsack light enough for summer wear but still versatile enough for year-round wear in a mild climate such as we have where I live.