I have been pondering a multi - use armoured layer for a while and certainly something that made riding in the heat more tolerable (especially my commute which has some low - speed heavy traffic portions in it 
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So, with my birthday money from June burning a hole in my pocket I took the plunge and ordered a Knox Urbane Mk2 shirt - I have ridden in it twice now (both in this hot weather, obviously!) and my first impressions are really favourable.
It is a really well constructed AA - rated shirt and the armour (for me) sits in exactly the right places. The armour is really soft and I particularly like that the back protector covers your whole spine and is brilliant as it flexes with you as you move, avoiding the “ironing board in the back of your jacket” feeling.
The fit is snug as it is supposed to be and I think it looks really good on it’s own. It can be worn with nothing underneath but I have layered a thin merino T shirt under it on both occasions so I can stop and unzip it without flashing other bikers who are simply trying to enjoy their brews and fry - ups 
and to protect it from too much contact with sweat! It is really easy to move in and I have tried putting on other clothes over the top of it; which is simple.
On the bike in the hot weather it felt absolutely incredible; it allows totally free movement and it’s easy to forget you’re wearing a bike jacket, I think thanks to the flexibility and softness of the armour. You get so much airflow pretty much everywhere which is a little alien to get used to but in this heat felt INCREDIBLE - I stepped off the bike feeling cool as a cucumber yesterday whereas @HelmutVisor was suffering a little in his perforated leather jacket. I wore it with my leather trousers which are pretty low waisted but the shirt is long and the back does not ride up at all. There are also elastic loops to stop the sleeves riding up when you put gloves on or put on clothes over the top of it, but the cuffs are pretty snug and I don’t think they would go anywhere.
I also like the look as it’s less heavy and “bikey” if you want to go anywhere and walk around, especially unzipped, or have to carry it.
My impressions so far is that it will likely become one of my very favourite pieces of kit due to it’s versatility; I’ll see how it fairs as the temperatures vary 
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