I don't know where the handbrake comes from. I have heard that it might come from a dumper-truck that is no longer made, but it could easily be a modified, off the shelf item. The ratchet seems to be similar to some kit car handbrakes. As for the shaft, the only one I can find that comes close, although not identical, is from a Jaguar XK120/150. TVR may have modified the assembly by brazing on a tail to which are bolted the twin handbrake cables, however, I have also seen illustrations of generic handbrake assemblies, which also show this tail, so who knows.
The handbrake clearly needed renovating, it had had a hard life exposed to the underside of the car. I asked a re-chroming specialist and it seems that a partial re-chrome, say down to the ratchet, isn't possible, which means the whole assembly needed to be stripped.
A clevis pin holds the ratchet dog against the ratchet, and that comes out easily, but the central button and the rest of the mechanism can't be released from the assembly until the thumb button comes off. Although it looks like its screwed to the push rod, in fact its held on by a pin, that simply drives out. The rod and dog can then be pulled out the back of the handle. There is a rubber grommet in the handle that seems to hold the rod to some extent, but it was mashed.
That left me with the handle and ratchet assembly. You can see that the main pivot pin is peined over to hold it in place. The only way past this is to grind or file it off, so thats what I did. The pivot then dropped out easily.
Heres the kit of parts:
I've sent the handle and thumb button off to the chromers. On reassembly the main pivot will be replaced with a half inch clevis pin and split pin arrangement.
So, after a months wait, here is the newly re chromed handbrake lever. Its been stripped and rechromed, including the tail section. The quality is excellent, I am really pleased with it. Now it just needs re assembling!