Thank you so much everyone who encouraged and supported me over the last few days following my unsuccessful attempt at this run a few days ago: and I've taken note that the F word (fail) is banned on this site
I plotted out a new route, around areas and mental distance markers that I am familiar with but where I never run and I have to say it made a big difference. I did forget about the flight of stairs I would have to run up and 2 busy junctions I would have to cross (and one of these was so busy I had to stop and then walk behind group of pram pushing mothers for ten seconds) but I did it and that's what counts. Surprisingly I found it far harder than the 28 minute runs and really struggled in the 15 to 25 minute sections but I was mentally strong enough to push on and made it to the end.
What I couldn't do was go straight into the walk at the end and instead I held onto a tree and prayed I was not about to have a heart attack or a lung collapse, but 30 seconds later I was fine and could walk, though not that briskly.
It wasn't the prettiest of runs and I missed my target of 5k in 30 minutes by an annoyingly small distance of just 240m, but I will nail that double objective by the end of the week - 5k in 30m. Its doable, though not sure my throbbing thighs and buns agree with that right now.
Again, thank you everyone for supporting me the other day, I needed that boost to get me back on track and confident in myself again.