Done it! and before I turn 60 (birthday tomorrow). Time 36:23, that will do nicely for starters.
So my next challenge is to get my time down to 30mins, I think that's going to take a while but I will definitely continue with Park Runs.
For anyone hesitating about their first Park Run, get registered now and give it a go, everyone involved is very friendly and welcoming.
Many thanks to the people who encouraged me after my last post. The support and encouragement is wonderful and continues to keep me motivated, thank you everyone.