I used white LEDs from
https://www.bettercarlighting.co.uk in the binnacle, for both instrument lighting and the warning lights, and am happy with the result, although I slightly wonder whether coloured LEDs might not have been better for instrument lighting as they are very sharp white. I think from memory that green or red are available. I left the existing feeble incandescent bulbs in the lighting over the switches and heating knobs and was pleased to discover that they provide enough current drain to enable the existing dimmer rheostat to dim them and the instrument lighting - if you follow the same course there’s no need to change the existing dimmer, presuming it still works.
One does wonder about the original purpose of the dimmer rheostat- how many degrees of invisibility did anybody need in the 1960’s?
I also put an LED in the interior light - a vast improvement altogether
Quite a number of owners don’t know that there should also be a neat little bulb in a rather well hidden mounting above and to the right of the ignition switch to illuminate the same. Very useful in the dark. This should come on when the drivers door is open, but magically doesn’t when the passengers door is open or the interior light is operated by the switch on the dashboard. It’s a tiny bulb but quite bright enough and I left it as an incandescent
Where did you get to with petrol in the boot?