Hi Dave
I'll chip in seeing as no one else has. I seem to remember that the hole is small so i don't think the pressure is too great. I believe it is pressure fed. Given the propensity for cost cutting at BMC, I would assume that it is needed or they would have got rid of it. Having said that, when I rebuilt my engine the banjo bolt feed was missing a hole which I drilled. As far as I could see, without it the feed would not have worked and the drive didn't seem to be worn. So maybe it isn't really needed. There could be enough splash to lubricate the drive. Someone with more knowledge than I might have a different opinion. Good luck.
Matthew