Are the 3 same dia holes located on the firewall just above the support panel used for the cables ?
Allen

I think the centre one is blanked off.

Ditto gtogreen.
That's what my 8/70 S has too. Heater cable through driver's side hole, choke through LH hole. I put a blanking grommet in the middle.
Some earlier minis did not have the centre hole punched out although there was an outline for it like the other 2 in the bottom edge of the dash panel.

The accelerator cable exits through the firewall in line with the top of the accelerator arm. It is below the firewall cross-member.