Booked in for a service, initial test drive I could feel it was severely underpowered, feeling like it was not making any boost.

Carried out full vehicle scan as we do to start all services. There were no fault codes stored, in the bay having a glance over live data the one thing that stood out was that 'measured airflow' matched 'required airflow' at idle, but as I raised the engine rpm, at 2000rpm measured was 320mg while required was 480mg. This was enough to know there was something worth chasing, so after carrying out the full vehicle service inspection some diagnostic time was sold to the customer.