To something like 3 x 2km or 3 x 10 mins off 2 mins to start with.
Or switch paces every 5-10 mins between just above/just below target, even if just to break the monotony
Or do a park run on a Sat morning as a tempo run first....sticking to your tempo pace which should be relatively easy given the company and the race feel. Then 2 mins after the park run start your 2 * 2km tempo intervals.
Thanks all – some good suggestions there. I did do some “tempo intervals” earlier in the summer which definitely felt easier than the pure tempo runs and made it easier to maintain a good pace for longer in a session. But then I was doing longer pure tempo runs in marathon training pretty well last winter, and I feel the training benefit is better (it’s closer to simulating a road race which is just one long tempo run) – and it takes more mentally to push through them which should be good race practice. But this was my first pure tempo training run for 6 months, so maybe it’ll take me a little while to get back into them and get the pacing right – will see what happens with my next one planned for next week and then consider experimenting a bit more after that.