Civvie clothing that does not melt

I'm trying to find a range of outdoor clothing for a hot climate that isn't so full of plastic that it melts at the first opportunity.

Does anyone have any suggestions? By the way I'm not looking for a cotton safari suit or anything in tweed.
Rohan clothing used to be very good when the Howcrofts still owned the company. Now it has become a sort of fashion company like all the others.
They still have some good stuff but you have to sort through a lot of dross to find the worth-while items ie Bags

Rohan LINK

You didn't say where you are going or what you hope to be doing.
I would add that if you are just travelling then go for the non-military looking option. Uniforms or anything that looks "uniform" type clothing can make people dangerously nervous
I wear M&S twill shirts and timberland chinos. Both cheap, cool and non melting. Rohan do a pure cotton waterproof(ish) lightweight jacket.