Initial Trice fettling - put pedals on, adjusting boom to fit me (I'm not short at 6 foot, but I could only just do pointy-toe reach to the furthest position). Then chopped down chain and tubes to fit, and adjusted the gears. I need to make a stand for this; I propped the rear up on a block of wood so I could spin the rear wheel and tweak things, but it was unstable. Just a lump of wood with a wider base and properly shaped at the top to locate the trike will probably work OK.
Found that I don't yet have enough movement in my dodgy knee to go through the whole circle (I didn't intend putting load on that leg, but putting it through it's range of safe movement would be OK pedalling with the other one). The cranks are 170mm, I reckoned that if I put a 150mm one on that side I'd manage - so got my youngest to dig the carcass of an old kid's mountain bike out of the shed. Crank pulled, and I find that the Trice has a very nice Shimano 105 chainset that is the original Octolink rather than square taper - should have checked that before sending my offspring into the shed of doom. So, scrap that idea as I don't want to get into swapping out the bottom bracket and entire chainset.
MrsH saw the removed section of chain on the floor, and asked if it didn't have a chain length adjuster. Apparently they've got a recumbent trike at her school that has a chain gobbler of some sort so they can adjust it for the kids. She doesn't know what make/model the trike is but she has ridden it - I've suggested that once I can actually ride this we go over to her school and have some races around the car park.
I rode it around in small circles a little bit, but will need to fettle a Steve Abrahams-style gammy leg support to do any more. Hopefully within a few weeks I'll be able to use it more normally (though powering through my good leg). Had a moment of mild panic when I got it going and didn't know how to stop. Of course, I'd checked the brakes, and knew where they were on the bars, but my sitting-down reflex instinct was that there should be a foot brake, rather than using my hands!