I've done it!
Having downloaded C25K a few times, I finally plucked up the courage and did my first session this morning. I'm going to the gym and using a treadmill because I know it'll work better for me, especially at this time of the year. But I'd kept putting off because I'd feel self conscious. But I started the app, put some good music on and actually really enjoyed it. I haven't run for well over 30 years so it was a bit of a shock to the system, but nowhere near as bad as I feared. Can't wait for the second session on Friday now.