Thanks Steve

I think this last patch of wet and cold weather isn't helping at all with the level of background pain I'm having to cope with at the moment. Today was wet and stormy with heavy rain (again!), but nothing like as bad as when the tropical cyclone went through. I don't think I could handle your sort of Winter weather though which is definitely for those who are far more intrepid than I am.
I really like the sound of what you've got planned for your trike. The De Dion Bouton tricycles (and those of similar vintage) are amazing and would make great subjects for a tribute replica.
Despite everything I've been able to look around for parts in the garage and do some sorting. So far it looks like I can go a long way along with the Colombe project using what I already have to hand. Internal expanding brakes are something I want to use, especially on the front wheel and after some looking around I found a Chinese supplier on the Alibaba website who can supply suitable hubs and brake parts. I've been buying all kinds of things directly from China for a while now, most traders offer free shipping and so far everything I've ordered has arrived in a reasonably timely fashion.
The brakes look superficially similar to the Chinese band type brakes that were commonly used on Chinese bicycles and e-scooters that were imported into NZ a while ago by several local traders. When the recession bit many of these traders went to the wall and I was able to buy a few of the band brakes very cheaply at clearance sales. They aren't a particularly fabulous brake for stopping in a hurry, but they do make good parking brakes. The internal expanding brakes look to be a further development and improvement on the band brakes, so I'm reasonably hopeful that they'll do what I want them to. They are a 90mm brake in case anybody's wondering.
My Velosolex trike project that was stalled when I was ill is going to be absorbed into the Colombe project. A few of the parts I was going to use for the trike are now being used on the Colombe, so I thought I might as well go all the way and use the clone Velosolex engine on the Colombe as well. It's just sitting in its box so I might as well assemble it onto a set of forks and use it. If it doesn't work out I can change out the whole thing, motor, forks, wheel and all and attach it to a spare solo Raleigh 20 frame instead.