Went to the physio last night about knees and found out 2 things:
1) I have very ticklish knees
2) he can detect no permanent or severe damage in joint
I also got a very detailed description of why being flat-footed can really knacker your knee and a bunch of quad strengthening exercises to do
Best of all he can't see any reason why I can't pick up running next week where I left off (at week 4 run 3) provided I can do various exercises such as 15 1-legged knee squats holding for 10 seconds at 15 degrees without pain.
Now I am just fidgeting waiting to do my next bout of physio exercises so I can finish week 4 and start week 5 and do that 20 minute run - my inner fatty is disgusted.