Sun finally came out again around 2:30 and I pushed off on Bonnie not long afterwards.
At the bottom of the hill I saw that the road grader had gone by on Under Bunker earlier in the day during the rain. Great for grading, extremely slip, flop and fly for a bike in slop.
Tuned me up for the very tricky night time return on the grassy approach to the Bonnie Castle, now scattered with wet leaves.