Just how difficult is the "Bad Step", especially alone and in the wet?
By way of preamble, I've done the step a good few times (including a jolly half-hour spent going up-and-down up-and-down to sort of 'memorise' it). IMO once you identify the holds (look out for a little polished knob of rock low down for your left foot) and get the moves sorted it's pretty easy to get
up. If you descend again immediately you may well find it hardly more awkward than the ascent - that was my experience anyway.
But - and it's a big 'but' - if you haven't done the step at all (or not for a while) it may not be immediately obvious how to downclimb it. And if it's wet and you are carrying a heavy load you may well find it problematic to get down safely.
Luckily you don't have to risk it in the wet with your loaded pack. There is a very easy bypass route ('the dog path') rising beside the step's gully. This route is very clearly shown in
karl h's photo - it's where the runners are descending on grass between boulders to the right of the picture. The dog path is on the the right going up - it'll be on your left coming down. I've walked dogs down there several times and also seen people taking their kids down that way.
How hard is the bad step? To me, the answer is largely subjective - one chap's doddle is another's challenge.
Anyway Nick, I hope you have a great walk and the rain holds off.