Found the timing chain tensioner to be very soft, bought new one from BMW/Mini for £13!! and was much stiffer.

Fitted it, live data on the inlet had the 5° difference as before, on roadtest the 2 codes 287D and 2870 returned in under 1/2 mile as before, cleared the codes and reluctantly continued roadtest to see the 5° difference between Setpoint and Actual cam position had gone and the 2 values on live data to be within 1°. Could this be the self adaptation?

After 5 mile drive all ok.

In future, when we get inlet Vanos related faults the tensioner will be the first thing to check.

Thanks for your help, Martin.