@Mr_K_Dilkington this is my best along this bit 22.7mph avg cad 97 avg h.r. 149bpm 2.7 miles with very slight overall upgrade, but basically as flat as you will get.
http://www.strava.com/activities/100163977#2143876811
I suspect without looking it up i had a tail wind or at least something out of the southern skies, segment for segment I compete and manage better times than people on bikes costing upto 10x what mine cost, though not so with the changes I have made, the one thing I can not do much about is the weight, and this is what slows me down on the hills, and longer runs, which is way I dont tend to ride much furthur than 50Km as a rule, though when I am fit I can do this day in day out, I am faster than last year, but not as fast as got to be last year, ok not quite as quick as last year, my avg for the last year was 15.07mph (and this includes Jan-Mar where I only managed 12-13mph, new wheels helped after this) over 8,662 miles with 397,431 ft of climbing with an avg cad of 79.8rpm this avg will get higher this year with the new gearing, but like I said I cant do anything about the weight till I can afford a new bike, my current bike usually weighs in at between 14-15 Kg's with mudguards and rack (can't be bothered to take it off most of the time), I dont see the odd Kg making much difference but 5 would especially on the hills.
I have included a table of my top 20 times on the above segment, I am currently 2mins behind my best, though so far the winds have generally been e or or northerlies.
Edit
Just to add to this my avg gear for this was 78.63" or 42x15 since at the time my cassette went 13-15-17-19 they were pretty big jumps, now it goes 13-14-15-16-17-19 so I now have better control over my cadence.