I ride Boardman SLR 9.4 with BB30. I agree that weather protection is an issue, the BB regularly starts "rumbling" after maybe every couple of months, especially this time of year. My simple solution is a ten minute job - whip the crank out, clean it all up inside re-grease and re-fit. Silenced for another couple of months.
OP may be having a different issue given frequency of annoying "squeak".