So I know this may be heresy to some of you but I would like advice on making my hybrid/MTB as good for winter road training as possible. I have a marin muirwood and have already put slicks on but would like to know what people think about changing handlebars to flatter with ends / alternative bars and whether there are better wheels (26') to make the whole winter training slightly less hard work!

you'll prob be fine with your slicks, maybe a set of mudguards to make it more comfy when its wet.

I stuck a set of bar ends on my mtb (in fact i've yet to take them off!) they are good for giving extra hand hold positions and i really believe they help me climb. That might be all in my head!

I admire you for planning on getting out there during the winter, i will be retreating to inside on the turbo trainer - or more likely the couch!