Found that one quite tough actually considering it's actually a minute less running than last week. About a minute into the second run I had to stop to the my trainer lace which had come undone so I felt like I'd ruined it. At the very end I ran for an extra 15 seconds or so to compensate.
Not sure I'm ready for an 8 minute run let alone a 20 minute run but I guess I can always repeat them if necessary. The important thing is I did it and can tick it off the list!