Paramo was a pioneer in a clothing category now broadly lumped together under the rubric of "softshell" garments. These don't try to keep water out by brute force, but rather use a combination of water-resistance and the user's own body heat to keep the user dry in nearly all conditions, as well as more comfortable. In the case of the Paramo designs, they are meant to literally "pump" moisture generated by sweat to the surface of the garment, where it can evaporate, freeze or run off. In contract, most waterproof-breathables will trap a fair amount of moisture inside before it can work its way through the waterproof layer, hence the need for massive pit zips and other ventilation devices. A good example of the Paramo line is the Alta jacket, an all-purpose mountain shell that is U.S. $300, 199 pound Sterling in your parts.
I haven't used the Paramo stuff as such, but have used some similar items from Cloudveil and from fabrics made by Cannondale. Patagonia also has borrowed from Paramo in its Infurno jacket ($250). I think the concept generally works very well - the only time it might fall down a bit is if you're hit with a really soaking rain, and for whatever reason are forced to sit pretty still for extended periods of time. So I wouldn't use one on a wet-weather steelhead-fishing trip in a drift boat. But for everything else, they should be great.