Hmmm - three Daves in this thread already, eh?
David (original poster) - I know little about this subject, but I'd go with what G8HQP Dave says. Though, as per davidgem, if you can post the model number, you
might get an unconditional yes/no response!
Ian (Orthicon) - you may find something useful in these threads:
https://www.vintage-radio.net/forum/...ad.php?t=67587
https://www.vintage-radio.net/forum/...ad.php?t=47092
where the topic of earthing has been discussed. I think I've seen other threads on this topic as well, which you may be able to discover using the 'search' button in the blue bar above.