Christmas comes early.
Well, after further thought, I decided that I wanted a pure 'warm weather' pair of trousers and that if adding water resistance meant increased heat, weight and price ... I didn't want it

. I already have a pair of cold(er) weather textile trousers for use in cooler weather and always have waterproof over-trousers with me (for heavy rain), so if I get a bit damp in a quick rain shower, thin enough trousers should soon dry themselves off in the sun and breeze.
With that in mind, I found an option that was cheap enough for me to act upon immediately (thereby leaving more money for petrol and ferries next year

) . Rukka's 'AiRider' trousers are, essentially, the non-water resistant version of the 'Airman' model, which was recommended earlier in the thread. At £180 (for last year's version, from FC-Moto), they come in at almost half the price of the current Airmans, yet still have the same Cordura AFT fabric shell and D3O pads at the knees and hips. Here's a Revzilla review

...
https://www.youtube.com/watch?v=sw18bozLCCc
I was very, very nervous about ordering them online, as the cost of returning them to Germany in the event of a problem would be quite high, but I put my faith in the online sizing charts and just went for it

. Anyway, the parcel arrived yesterday and I was highly relieved to discover that the size that I chose (54) was perfect for my 36" waist and that the leg length (C2) was a reasonable fit for my (quite long) legs. I'm 6' 4" and instinctively wanted to choose the C3 leg length, but an extra 7cm seemed like a lot and the last thing that I wanted was to have the knee pads hanging down below my knee caps (as has happened with a pair of extra length Kevlar jeans that I bought in Germany

) . When standing in the AiRiders, the bottom of the leg just rests on the top of my foot and when in the riding position about a third of the boot is exposed and the knee pads sit perfectly in place. Only when sitting on a low seat, like my sofa, do the legs ride up to nearer the top of my motorcycle boots (
a la Captain Kirk

). I'll assume, then, that I chose the right size

.
As for the quality and comfort of the trousers, they are far, far better than the 'RST Adventure II' trousers, which I rode with this past summer. For a start, the Rukkas are much lighter to wear (even compared to the RSTs without their thermal lining), but the biggest boon is that the knee pads are pushed in from the outside of the trousers and so the lining on knee is smooth and unbroken (by Velcro tabs and pockets). This stops the issue of skin abrasion from the edge of the pads and as the lining is softer than the rather harsh (nylon?) of the RSTs anyway, the trousers feel a lot more comfortable.
Another plus of the AiRiders is that they have an internal layer of padding around the seat, which acts to keep a layer of air between your skin and the saddle, thereby helping to reduce saddle-soreness. The pockets are in 'jeans' format, but I don't tend to put much in my trouser pockets when I ride anyway (a handkerchief, a few coins and a plastic comb, perhaps), so that doesn't bother me unduly.
I have yet to give them a try on the bike, but I feel optimistic that when I do ride in the warm weather again, these trousers are going to offer me the best chance of avoiding having sweaty legs (without resorting to non-protective alternatives, like denim jeans

).
Without the help of everyone who's contributed to this thread, I probably never would have discovered these particular trousers and would probably have gone and made another expensive mistake by buying something else. So, thank you all and have a very Merry Christmas

.
Andy