terry wrote:

2) It MIGHT be possible to get rid of gas in a tube by reheating the
getter; there might be active 'getting' material left? No expert on
tube manufacture but understand those getters were heated by RF. So
could be done again?

You can heat them again, but it will be to no good purpose. The getter
is a tray filled with a getter metal, such as barium. The tray is usually
in the shape of a loop so that it is easy to induce RF current into the loop
and heat it very hot. The metal all evaporates and deposits on the cool
glass (usually) It is very unlikely that there is anything left over.

-Chuck