Hmmmm,

I wasn't suggesting they were - in fact most definitely are not suitable - I only posted the pic as it's easier than trying to describe where the relays are, and also because by showing all of those in the cabin I thought it would help someone trying to differentiate between them.

The original post does say 'get a relay rated 30amps'

Also I see someone has now posted re not switching the headlamps via the panel switch so as to avoid cooking it.

Yes this was the arrangement in later cars, but PLEASE NOTE following my suggestion will not alter the current carried by any of the existing switches, it will only break the circuit when the ignition is off or cranking.

The suggestion describes the simplest method of achieveing what was posted - switching the headlamps off with the ignition. Yes it would be better to switch all the current via a 1986 on headlamp relay, but this requires a fair amount of modification (and had dim dip as well I think).