Jimmy Doug
If you know what's good for you ...
Myself personally, I've never enjoyed riding so much as when I learned to stop worrying about average speeds and times and so on but to just, as another user has said, get out and ride. You don't need to try to break personal records to get fit: just get out, spin the pedals, have a good diet and, most of all, just enjoy being outside in the sun...or rain...and have fun! I learned all that in your neck of the woods - Wiltshire man myself, or was until I became a Picard. I used to time myself riding up the White Horse. Now I just let the pedals turn and listen to the birds singing. Age maybe?