Thanks to Paulr33's advice I've been watching the AF 's on the micotech, I assume these are what the ecu is doing, not the actual ratios, at 78ks in 5th 14-15, in 4th 11 flat, this all depends on load as both rise on a hill but in 5th its much more up to 17, while in 4th not much at all. At 58ks in 3rd/4th its the same.
I now drive a bit different to before, where I hardly went above 3000rpm, as thats when boost starts, but now I understand that to acheive boost the ecu loads on fuel just as I was backing off and wasting that. Have I understood this correctly?
What I try to do now is keep the AF's in the 11 zone and to do this I take it that bit futher than before.