I was happy with today's run.  I did the Bromley-by-Bow loop and it took just over 45 minutes.  This is a reasonable time.  I started off slowly on purpose and intended to hold myself back whenever I felt any strain.  There were times when I could stretch my legs to capitalise on this restraint earlier on.  It is interesting that I ended up with a time similar to what I would get if I had gone out stronger from the start.  This further supports my theory that I start of slow and need to get warmed up before I can run these long distances.