This is more complex (and very unusual) due to there being no named RK.
The blue badge holder does not have the V5c so on that basis they would be the RK.
Motability have some sort of system with DVLA, so the RK
is the PIP recipient, but Motability hold the digital documents/info from DVLA to deal with the admin side of things (like tax).
From memory, the RK is listed down as two fields:
Identifier
RK Name
Address
PostcodeSo it may well be that ECPs systems have just taken the first "identifier" field, rather than the RKs name.
That in itself is quite interesting, as although the identifier is unique to the RK, the RK probably doesn't know that number is them...