I gave up office work last year due to severe repetitive strain injury in both hands, arms and all finger tendons (but not my wrists strangely), as I'd spent years using mouse and keyboard incorrectly and for hours at a time without break, be it working during the day or playing games all night. I probably should have sought advice as to what I could do without using my hands too much but my brother-in-law trained me as a w/c and it seems ok. Recently I have felt tingling in my left hand, maybe I'm spending too much time on the computer again, or maybe the trad work is affecting me again, I don't know but I'm worried.
Tony, it def sounds like you need to do something last week, not tomorrow. I waited far too long before seeking help with my RSI - I'm 25, had this for 18 months, and am scared of arthritis and carpal tunnel in the years to come. My physio gave me stretches to do to stop the tendons tightening, which work when I remember to do them.
If you can afford the 4-6 weeks off work do it - I researched various websites recently due to the tingling (which hasn't come back thankfully). The surgery procedure is something like cutting a piece of the tunnel out, to make it wider. Obviously it'll swell while you recover but should be good again after, as long as you don't abuse it and take it easy.
Pj, I can't believe you still clean windows with what you go through. No offence, but I hope I never get there, I still hope that if I take it easy, it'll mend itself. Wrist supports are no good for RSI as you need to keep your wrists free, just don't use them as much, and stretch them. They may be good for sleeping as they will stop you bending them when you turn over etc.
Try taking ibuprofen to keep the swelling down, and put frozen peas on your wrists. If you have to work, work slower and try not to grip poles, squeegees etc so hard, it all helps. Am sure the cold weather isn't helping either, but then putting your hands on the radiator is no good for the swelling!
Chris