I did this when I rebuilt my 1980 Plus 8. The original rocker switches always seemed to fail at the most inopportune times, so there was no way I wasn't going to get rid of them. Used sealed switches from Car Builder solutions. I think it was this general type. https://www.carbuilder.com/products...-return-off-on-spring-return-double-pole

I identified the hazard switch with a bit of red shrink fit tubing over the toggle.

I remember having to find a washer to fit in the dash hole to get the size right and think it was these.
https://www.holden.co.uk/p/toggle_switch_threaded_washer