Completed my December ride today - obviously with two months missing, there's no reward on offer, but I'm glad I did it, as it proves that I was able to get through the hardest four months (Jan, Feb, Nov, Dec - only one of which I had ever managed a 100km ride in previously) and gives me confidence that I should be able to complete next year.
It was actually quite a good ride too. Made a late choice (i.e. as I got to it) to detour and climb Brill Hill from a different direction that I usually would and surprised myself with how easily I made it up there. Bike caked in mud when I got home though - while it didn't rain during the ride (and I don't think it had overnight either), because of the thick cloud cover the roads just weren't drying out and it was spray city everywhere I rode.