I completed W5R3 this morning and enjoyed it. I had loaded my own music onto my mp3 player (a collection of cheesy rock tracks from a CD called "101 Running Songs"), so after listening to Laura for the 5 mins warm up, I switched her off. The songs are all at different beats per minute and I think I ran a little fast for the first 5 minutes as I was tiring quickly. Then 'Runaround Sue' came on (see I told you they were cheesy!) and I caught that beat and ran to it. Apparently this song has a beat of 138bpm and I felt this a comfortable speed.
I managed the 20 minutes and kept going for another 3 minutes to take me to the edge of the woods again. Looking at MemoryMap, it was about 3.25km for the 23 mins running, so not fast, but not too slow.