I actually drove to my old stomping ground tonight (where I used to live) for the first run of Week Five. There's fewer inclines and I felt like I needed flat roads this evening. I also had a strong black coffee beforehand (for warmth and a 'buzz').
Not sure if it was the caffeine, the lack of hills or whether my fitness is improving overall - probably a combination of all three - but those five minutes didn't seem too bad at all.
Next run Saturday !