What I was thinking is that I've read the emissions update could potentially be causing losses of power at low revs (<2000rpm) but of course, information is few and far between and far from conclusive. BUT It would match perfectly with my current experiences - if s-tronic hasn't been updated to take account of the (supposed) difference in low-end power, it would think D7 was ok with this load at this speed. When the engine fails to give the required power and more throttle is required, s-tronic thinks I'm trying to accelerate away and drops a gear.