Happy Valley tempo run

7 weeks until the Gold Coast Marathon so maybe it's time that I started training a bit more seriously. It rained all of yesterday on or off - sometimes a vaguely irritating drizzle, sometimes a downpour. Luckily by the time I got on the tram to head over to Happy Valley, it was chucking it down, and the wind was building up too (and this only increased over the evening).
Having spent all day stupefied through lack of sleep the night before, I wasn't really looking forward to this, but got lycra'd up and starting jogging round the track - did two warm up laps, and then a strange vision went past me - a big bloke wearing nothing but a very short pair of shorts and some shoes, despite the rain. Greyhound tendency engaged, I ran off after him and for the next 5 laps, we were pretty much hitting the same pace; on the flat, nothing to separate us, on the downslopes I'd lengthen my stride and open up a gap, and then on the slight uphills he'd catch up. Normally you'd think the more heavyset among us would do better with gravity assisting rather than fighting us, but I guess it may be less comfortable to run downhill the bigger you are, and they're not steep enough hills in Happy Valley that the extra muscle weight would be a hindrance running up them.
So HV's outer running track is about 1400 metres, and I'm aiming for a 3:30 again (would like to beat my Tromso time from 2 years back, but we'll have to see...) so pace would be 8 minute miles / 5 minute kms, and so I should have been putting in 7 minute laps. Instead (average heart rate in brackets):
6:31 (160)
6:36 (165)
6:43 (166)
6:48 (161)
5:52 (174)
Not entirely sure where the last one came from; I thought it was actually slower than the others and that the reason I was beginning to hurt was because I was getting tired out. Did another two laps to cool down and I was done in 1:05, which seems fairly respectable. Bear in mind those 5 laps are 32.5 minutes to do 7k, which gives a 10k time of under 47 minutes, and a marathon at that speed would be over in 3:15; which makes me think maybe I haven't been pushing hard enough at race distance (would usually see a heart rate in the 150s). Speed session on Thursday night - hopefully it won't be chucking it down with rain...