The technology seemed determined to defeat me; first the heart-rate monitor strap decided the battery was flat, so I swapped that one and got it working, then the cadence/speed sensor wouldn't connect, fiddled a bit and gave up. The old roadie on the trainer will not stay put, doesn't seem to matter what I do, the damn thing gradually creeps along the shed floor, so a few interruptions until I managed to wedge the front wheel against the door frame. OK, so there we go, about 20 minutes at about as hard as I can go, 161bpm average. All up three quarters of an hour and I think after all that I didn't really come up with anything that I didn't already know -- other than that I need to stock up on CR2032 batteries