Hi Dylan,
This type of dash, yes?
If so, I think the padding is symetrical, so if you need to look outside SA to get one in good condition, a LHD dash may do the job for you.
I've never removed an old type dash, but if it's any indication, the later type (as in my '73 164) needs the dash out to remove the top padding. (It
might in theory be possible to remove with the dash in situ, but it would be so awkward that it would actually be quicker to remove the dash). And the old type looks harder because the padding surrounds the dash.
The good news is that removing the dashboard is not the horrific job that it is on a modern car. Just work methodically and label wiring and you should be fine.
A rev-counter suggestion: in my '69 164 I fitted a Triumph rev-counter into the main dashboard. It was the right diameter to fit neatly between the upper an lower padding in a hole cut next to the speedo binnacle (with the switches moved along a bit).
The font looks Volvo-ish so it looked much more like a "factory" installation than a pod mounted tach would. This one's in a Stag, but they also exist in 4 and 6 cyl versions.
It looked good alongside the strip speedo; pretty sporty. I don't have any photos and I can't do photoshop! The nearest approximation I can find is this OE Rover P6 dash
Anyway, pls let us know how you get on with the dashboard! If you need me to look in the UK give me a shout, but shipping might be prohibitive.
Cheers
John