I've posted about not being able to get past W5R3, so have been building up to it doing 2 x 10 min runs with reduced walking intervals in between. I've gotten down from 5 mins walking to 2 mins.
I felt like seeing what else I could do tonight.
I did my best run to date! I ran for a total of 41 mins; 11mins run (2 mins walk) 12 mins run (2 mins walk) 14 mins run. 4.28km in total.
I'm pretty chuffed!
I will be continuing with the programme to conquer W5R3. ;D
Excellent.
I don't see any physical reason why you can't now just go and run for 20 minutes.
Breathing!....I seem to need a break mid way. Once I have got my breath back after the first 10mins I can run relatively comfortably. I have tried slowing down and this did help, but I am hugely unfit and this seems to be working.
Have you tried to do 5 min run as a warm-up? Before you start 20 min chunk? Usually there is this 5-15min of the beginning of each run(ing day) as kind of body switch / body adjustment. It is physical thing, but you can push through it mentally knowing that after that beginning period everything will be fine. I think this is what W5R3 is supposed to teach us 
You can cheat a little by adding this 5 min run before
Well done for running so much and for figuring out your way to overcome the problem! You are in perfect mindset. Now, you just need to believe in yourself, and push this uncomfortable moment through, if needed by slowing down ALMOST to walk. Then, your body will get the rhythm and breathing back
Good luck! I believe in you!
Tanks IgaT, I hadn't thought about adding 5 mins before the 20, I will give that a go. I did slow down on the long run last night. Will combine both bits of advise and try and crack it this week.
IgaT is correct. That's the 'Toxic 10' when your body goes into oxygen depletion. Poppy posted an FAQ about this:
Great... now smash that 20... you got it
A bit of a jump 
Bit of a step up?
App timing has messed me up…help!
W5R2 - what's the point? 
On a bit of a downer........
