Well, you don't seem to know how to deal with it? You mentioned fault codes, not I. EICR's are usually done by folks who have the relevant experience, which is the key here.
For what it is worth, the regulations do require it to be isolated, but this can be achieved by using the MCB in the CU, so as far as the regulations are concerned, that is sufficient. In reality, it is good practice to provide a local isolator so that the shower can be turned off in circumstances such as it malfunctioning and not responding to local controls, or bursting into flames or suchlike, or needing to be fault found on or replaced, although in such a scenario I would personally lock it off at the CU. Pretty much the same as washing machines or the like.
If I was doing the EICR, I would probably C3 it, personally, but this will be open to debate. At the end of the day, it is down to the experience of the guy at the coal face.
