Well every minute of that was a struggle, I just felt completely lacking in energy!
I think I was a little dehydrated before starting, and a seriously stuck dropped chain about 7 minutes after setting off didn't help, as I had to adjust the chain catcher to free it and then start the ride again, by which time I is was no longer warmed up.
Thanks to Kipster for the encouragement, quite an interesting end to a long climb, a bit too far for a sprint, not downhill enough to freewheel, so just flat out for the last minute or so.
I think I may have to try that again, when I'm feeling a bit more energetic. I hope I'm up for tomorrows group ride ...
Geoff