I have a full RBBB.
It was investigated at OASC when I joined the RN to fly - I never even got told about it at the time and nevr knew I had one... it is so inconsequential.
The only reason I found out about it was when I went for an RN pre diving course medical several years later - the duty PMO came into the room to speak to me (he wasn't doing my medical but had been asked for advice on the ECG), because he said he thought he had recognised the ECG. Turns out he had done my initial medical at Haslar many moons ago.
Again, no problems with the fact I had a RBBB, so I was able to both fly and dive for the military.
Several years later at a loose end, joined NATS and as it was an initial issue of a CAA class 1 medical, I had to undergo a 24hr tape test. Again, it proved that it was 'just' a RBBB and there has been no problem ever since.
Every time I have an ECG, the RBBB shows (obviously), but it is never an issue as it is stated on my notes that I have RBBB.
The only reason it is investigated in the initial issue medical is to ensure that the abnormal ECG is only due to an RBBB and not masking anything else.