It takes time and every ride is different, just keep at it, even the merest of a breeze can change things, if your weather has been anything like ours its been pretty calm the last two weeks or so, so if you have been riding in those sorts of conditions and then get a bit of a breeze it will effect you ride.
On another note, ordered two BB from
Wiggle on Sun here this morning, even next day costs wouldn't have been any quicker.
because as yo may be aware I will be changing the front chainset and these were to good an offer to miss, just need to save for the chainset now.