Hi Bizzy - I have written about this once before, I'm no authority (as am only a mere FW & RW pilot) I have partial RBBB. I was told by the CAA that they would just keep an eye on it. No restrictions and no snags unless the characteristics of it change. My understanding of it is that it is a conductivity/timing issue (but the Ticker Doc's will obviously expand on this). I was able to have a CLass 1 without any bovver.
However, the Heart DOC who examined me when it was found told me that it was a very often found in very fit people. I too spend much time trying to keep myself fit. But after they told me this - I thought time to eat even more curry and drink even more Guiness........such hardship.