Well almost three months have passed and I'm well and truly converted to fixed.

I've clocked up just under 900km fixed after I switched from 48x18t freewheel to the 16t sprocket.
The epiphany for me was the realisation that I can 'freewheel'... or rather, just relax my legs. A case of programming my mind to switch off the legs at will, and let the flywheel carry them. Learning to do this at times when I would previously have tensed up, e.g. reacting to hazards, has almost become second nature.
Since I went fixed I've only once been caught out - swerving a pothole - and it was no more than a gentle reminder 'kick' from the pedals.
Another challenge for me was stopping, especially stopping abruptly. My technique now is to unclip one foot and get out of the saddle and let the crank rotate and flex my other leg as I come to halt. It's tied in with the freewheeling to an extent I suppose, just with one leg though.
As for hills, I worried about Arthur's Seat, the closest local Cat 4 climb, but tried it and set a Strava PR.
I also managed a few other Cat 4s in the area on that day.
My new extended commute has some quite lumpy bits - very short climbs with up to 16-18% - and I can manage them - just about!
Suffice to say fixed is my new preferred riding. So much less cleaning for a start - you don't realise how much mess a rear derailleur makes until you don't have one. These days I save the geared bike for club runs, sportives, audax and other very long/hilly rides.
Happy days!
