Yes, they area early XJ6 push-push switches. Lucas part numbers are head: 30870A; side: 30869A; fog: 30868A; rear fog: 33878A.
There is nothing wrong with the switches but AC failed to put a relay in the circuit so all the current goes through the switch hence they can burn out as Graham mentions! Ian Winter came up with a plug in adaptor which adds a relay, reduces the current through the switch and increases the light output from the headlamps. I'll dig out the article and put it on the Members' Area.
They never used toggle switches.