Ah ha, not so fast after all !
Pulled away at the lights on motorway slip road on a corner, held him in 1st. Changed to second and he was very slowly pulling ahead, Blast ! rev limiter hits early as engine has only been running 5 mins max and now his tail lights are level with my headlights. 3rd gear and the distance remains the same up to 85. Slip it into 4th and hold speed as traffic is in the way. See the cars ahead pull across (now both doing 70). Down to 3rd and right up his arse all the way to 105 and no probs.
So the concluding fact seems to be that the difference between a cold Cup and an Elise is not just 5.8 secs against 6.5 secs, but more accurately the lenght of 1 Elise !
Next time I see him lets hope the engine is warmed up.