I don’t mind knee warmers on a day where I think I need the extra warmth early on (or late on) but will eventually take them off to ride in just shorts(you know what I mean). The problem for me is – if you put them over shorts they slip down, if under shorts the shorts ride up. Mine have gripper on as do short legs. I find gripper is ace against skin but doesn’t “gripper” lycra.My experience of 3/4s is Alexa many years ago which were ok but no longer about. Endura – excellent and below your £80 target. Rapha Cyclo-cross almost twice the cost of the Enduras but I have to say that the pad is the most comfortable I have ever used. They are the ones I use for longest toughest ride. Are they twice as good? Hard to say apart from on those rides when you are saddle sore and think “I wish I’d put the Raphas on”. Also nice touch – webbing bib straps, nice low front on bib making peeing easier/less messy and even the little key pocket on the back is good (for keys).
If I could only afford £80 though I’d consider dhb and Altura too.