Thanks everyone. Did the run today it was hard but I am sure it was a good session. YD you were right it was still VO2 max workout too. I had to do it in a lunch break so not enough time to take longer breaks and make it even more of a pure speed session.
Not sure Cliff quicker then my 1500m pace and probably with longer rests but not sure exactly how quick or how long. Maybe 400 or 800 pace with nie big breaks of say 5 minutes. Thats a guess though rather than any knowledge of how to train for a 1500.
Cheers YD. All sensible advice. I should be able to work it out myself really but I have never trained for 5k before. Done 10k - Marathon. 5k's have always been sharpeners rather than training for one in its own right.