If you've never done the trip single handed before (or equivalent) then I would strongly advise against making your first crossing at this time of year.
I have single handed a Sigma 33 cross channel twice and sailed the same boat double handed to Cherbourg at Christmas. Not sure I would want to combine both events.
Bray was meant to be our second stop but we had to come back with the wind gusting 32 knots ENE after an aborted entry where in the dark the sea seemed to be heaping up. It was a miserable cold night on the way back without a sprayhood.
I think it comes down to you, are you in peak end of season yachting condition? On the occastions mentioned above I felt A1 after a season of racing and a couple of JOG races.
My preference when planning such a crossing is to plan for 1 night at sea to eliminate the prospect of a 2nd.
I've done it singlehanded a few times in my little boat - you certainly won't have any trouble finding your way to Cherbourg, even if you do arrive in the dark.
The only reason I would think twice about doing it singlehanded this time of year is the wind chill factor. If it gets too rough/annoying for the autohelm you spend all the time upstairs trying to keep the boat going the right way. If it's raining and rough you get very cold and you can't really go downstairs for too long to warm up. You can of course heave to for a bit, but realistically you need to be averaging 4.5 - 5 knots or else the trip seems to take forever.