Update time...
I gradually increased the riding time throughout February, and finished with a ride of 90 minutes. I felt that I wasn't sitting “square” on the bike – my arms were telling me that I was turning slightly left all the time. I thought this was caused by my injured leg not being as flexible as it used to be, and so I was moving the hip forwards to compensate - which moved the shoulder forward - which affected my reach to the handlebars. I moved the saddle forward to see if it helped.
At the start of March I was getting a lot of pain in my leg. Not from the hip, but just above the knee. I decided to have a week off cycling to see if it cured it. It didn't. There was no improvement at all. So, I went back to riding, and stopped doing the physio exercises

. That fixed things, and after a few days I was fine. I still left it a week before I restarted the exercises, though.
I dropped the riding back to a lower level (that is, shorter rides but at the same intensity) as I felt that I was trying to improve too quickly. Cadence was now about 90% of the pre-accident level. Speed was a bit lower than that, because I was also using smaller gears. I saw the Physio at the end of the month, and the “homework” he gave me was to ride on the road before my next appointment in 4 weeks time

.
By April, I was hobbling round without crutches, and riding for about 6 hours a week. Generally, steady rides in HR zone 2 with some z3 and z4 work thrown if I felt like it. I still wasn't comfortable on the bike, and fitted a shorter stem to try and make me sit a bit further forward and be more upright. It felt better, but not spot on. On the 10th, I rode outside for the first time

. I used my mountain bike because I wanted the option of lower gears, but as it turned out I never used the smallest chainring. It was deliberately short and easy – the biggest problem was getting on and off the bike. I can't get my leg over like I used to

. I have to throw my leg up and over the top tube and then pull the bike towards me. Ungainly, but it works.
I went back to the turbo, because I didn't want to ride on wet roads, or in strong winds. I didn't feel confident about my bike handling, and wanted to have the weather in my favour. At the end of the month I did 3 more road rides, the longest was for just over an hour. Cadence was nearly normal but speed was still well down. I've been told not to attempt any high-power efforts so I was having to nurse myself up the small hills - I'm still avoiding the big ones

. The injury was nagging at me occasionally, especially when I changed my pedaling rhythm.
I still wasn't happy with my riding position. I know that the injury has shortened my R leg, because I did the “heels on the pedal” test for seat height, and the L leg reaches comfortably and the R doesn't touch the pedal at all. I didn't want to drop the saddle any more as it was already too low for the L leg to be properly stretched, so I moved the R cleat forward to pull the leg back towards the saddle. I now had to pedal with the ball of my foot behind the pedal axle, which was uncomfortable at first but I soon adjusted. I had to move the cleat a few times over the next week or so, just by tiny amounts, until I found the best compromise position.
It's now May, and the physiotherapy sessions have finished though I'm still doing some of the exercises. I've been outside a few more times. The longest was last Sunday - 25 miles, including riding past where I fell (but in the opposite direction). It was windy on the tops, and I felt very unsteady when I had to corner on a damp surface from the previous night's rain. The bike was twitchy and not handling well. I felt I was too far forward and hanging over the bars. Afterwards I refitted a longer stem and moved the saddle back to try and stretch me out again. I did another road ride midweek and felt a lot better, but I daren't lean the bike into corners like I used to. The problem is worse on downhill bends with a wet surface. It was very kind of Wiggo to show the same fallibility in the Giro - made me feel a bit less like a prat. I'm still slower than I was, but I think the leg muscles haven't fully recovered yet (they certainly haven't stopped hurting), so I'm hopeful it will improve in time.
This post was prompted by the fact that I've done over 1000 miles since the accident. Admittedly, nearly all of that is on the turbo but unless we get a good summer that's the way it has to be for the moment. Thinking back to where I started from in January, I have to be pleased with the way things have gone.
I said when I was in hospital that I'd do a 50 mile road ride by the end of June. Weather permitting, I think I can make it.