A bit late perhaps, but just found your thread...
I've had patellar tendonitis since Feb. Have been seeing a chiropractor (for back problem) who advised either of 2 options:
1) for non-athletes, total rest, perhaps 10 - 12 weeks, to allow affected area to recover,
or
2) for must-do athletes, keep going with low-strain effort i.e. no high gears, no out-of-the-saddle climbing, no sprinting efforts, etc.
(1) would lose all fitness in the legs, not just the knees, so was not an option pre LEL. I chose method (2).
Did 1.75x SRs pre LEL on wet and hilly events (in hindsight, the best training in the raining ever, for LEL'09). Knee pain persisted in fluctuations, but not in LEL itself. 10 months on from 1st diagnosis, tendonitis is now easing. (Completed RRTY despite knee problem.)
The chiropractor also highly recommended icing after all significant exercise. This eases swelling. Also told to avoid ibugel, etc, as these only mask the symptons. They don't repair the problem.
In my case, my dodgy R knee joint was"slacker" than L knee - worn out/age. Stretching the over-tight ITB has helped. But the real healer is time, reduced intensity and ice-bags.
Spin those twiddly gears...