No, the gas analysis (MOT) is out and that confirms the reading of the sonda lambda. I have 9 months to sort it out before I have to do the first MOT.
I am informed by a very competent person that fitting TBs and a supplementary ECU will fix the problem
As I mentioned before it is a common problem with sports exhaust systems.
PS. The sensors are working but it has been suggested by one workshop that a faster first sonda lambda may help and that may be worth investgating.