There are three Routes to Certification through the LA Building Control on the chart. 

(a) inspect

(b) accept EIC

(c) use an inspector 

That has to be an anomaly in route (a) because no one complete a BS7671 certificate. 

The anomaly in (b) is no one other than the unregistered installer sees the work and the installers competence is not verified. 

There's is not an anomaly in (c) because the unregistered installers work is inspected, certified by the inspector and the LA verify (presumably) the inspector is competent rather than the unregistered installer.

Basically the chart is s list so work arounds to circumnavigate what should be a straightforward process and the anomaly highlighted in yellow is not the only one. 

Sparkingchip said:

The anomaly in (b) is no one other than the unregistered installer sees the work and the installers competence is not verified.

That all depends upon the LABC. In deciding whether or not to accept an EIC, a responsible LABC would have to consider whether the author is competent or not.

It is perfectly possible that a diligent LABC may do a better job of confirming an installer's competence than a scheme might do.

Sparkingchip said:

The anomaly in (b) is no one other than the unregistered installer sees the work and the installers competence is not verified.

That all depends upon the LABC. In deciding whether or not to accept an EIC, a responsible LABC would have to consider whether the author is competent or not.

It is perfectly possible that a diligent LABC may do a better job of confirming an installer's competence than a scheme might do.