I have finally completed it, at probably the 4 or 5 attempt, (I normally end up straining a calf or achilles because of impatience, try to go to fast, and simply not taking the right precautions)
I like to think I've have leaned a few lessons along the way.
I'm a bit heavy (BMI currently = obese), and I'm trying to do something about it but I weigh quite a bit more than I did when I played on the wing 30 years ago.
So I warm up for 5 minutes on on a non impact exercise machine before I start, then gently stretch the parts I know can be problematic, then I start, and after the warm up walk, I jog slowly and try and focus on my breathing.
It currently takes me about 37 minutes to cover the 5K, but it's a big achievement to do it without stopping, and as I slowly reduce my weight and my fitness improves ..., well at the end of the day does the time really matter, who am I trying to beat.
Completed my first park run on Saturday and looking forward to doing many more.