Didn't feel at all confident about it, but went out in the sunshine and slogged through it. First ten minutes were as tough as ever (though also slightly uphill), then there was a patch in the middle where I actually put a waypoint on my garmin saying 'good', because I felt pretty much ok, but was sure I wouldn't remember it like that by the end! The second half was a bit downhill which helped. Seems a blooming long time though!
Still slow (5.9kph, so slightly better) but a total of 2.7k in 28 minutes, so that made distance and time personal bests, but not likely to win any prizes!