You may have seen that Terence (the trailer) sported an electric winch at Mylor this year. The winch is more than powerful enough to draw Vagabond on to the trailer (even on the steep slipways at Northney). When the winch wire is led over the bow roller and connected the forestay, the winch will raise or lower the mast too. The use of the remote controls make all of these operation relatively simple "one person" activities.
The winch is Warrior Ninja C2500 12v winch fitted with "synthetic rope" - I found mine on the web from Auto-Lift UK Ltd.
The winch is powered by a hefty 12V battery in a box on the apex of the trailer. The battery can be charged from the car (using the fridge connections of a 13 pin trailer connection) or by the on board 35W solar panel.
Photos of the winch on the modified winch bracket, the box containing the winch battery and the controls can be found at
https://www.dropbox.com/sh/7tm9emg2ashxugm/AABb9mOHGY8Cphyn6ufz2utma?dl=0.
There's also a short clip of it in action at Northney.