I finally managed to get myself into "PBP is almost here Mode" and keep the calories down. Currently I can't see why I would ease up on the diet.
Strava really highlighted the issue because it cleverly estimates your power output (based on Speed, weight, gradient I assume). Clearly it's not perfectly accurate BUT what it does show is that I am putting out more power on the hills, than the lightweight cyclists, and going slower up them.
Once you get to a decent level of fitness and endurance, initially more important than weight I think, then you reach a point where you are battling the Power:Weight ratio. I am battling it and losing it seems.
Anyway, I'm heading towards a good place regarding fitness and weight now. Strava has also helped me on the fitness front as well.