Well, my second 25 minute run went off well tonight, I pushed a little bit harder and at the end of the run I had run further (.14Km more) and upped my overall pace by .35Kph compared to Monday's 25 minute run.
Not a big improvement I know but an improvement none the less
These longer runs are a bit of an experience, it gives you plenty of time to sort out your pace and breathing and modify either as required - quite enjoyable.