Well that was a mistake. Had a chance to go out on the bike yesterday afternoon and turned it down cause I thought it was too cold (my weather app at the time said 4 deg C, feels like 0) and too late, so did an indoor Zwift spin instead. Got up this morning knowing I was going to force myself out no matter what, but took a look at the app anyway - max of 2 deg C today, will feel like minus 3 - just great.
Got all layered up and picked an easy route, albeit one into a cross/headwind on the way out, in order to make my return journey a little easier. At first it wasn't too bad - a bit slow going, but road conditions seemed okay. Then as I turned on to a single track lane, I saw that it was very wet, which I thought was strange as we hadn't had any rain here for a good few days. It turns out that this road just doesn't seem to get any sun and round the next (blind) corner, the ice started. I saw it just in time and managed to slow myself right down, but I still lost control - because of this, it was more of a comedy topple over than an actual "off", but even with all my layers it still hurt a bit.
Walked the rest of that lane just to be sure (was only about quarter of a mile long) and then from there, stayed on fairly major roads, although I did have a near miss with more ice that had formed under a railway bridge that I only saw at the last minute. Eventually got the 50km done and got home and tended to my wounds - grazes and bruising to my left arm that I put out to cushion my fall and a small cut just above my right heel where it looks like the chain or the cog ripped through my sock (all fairly superficial though).