Does anyone know where or how I could acquire either a full Eleco Way lamp or just the diffuser?

Do you know the specific model number, HW 877?

Hi, I am not 100% certain but have attached photos to this reply if they help?
I am under the impression that they are HW 877 but thats third hand so can't be certain.

Are you located in Australia? Those lanterns pictured are Raymond Industries Wyt-Ray post tops, over here in Canberra there are still a few from the late 60s lighting the minor roads!

Oh that makes so much sense because yes we are in Australia. We are in Victoria. Do you have any ideas where we might be able to find these to purchase? What LGA they are in maybe and I will reach out to that council?
Thanks, this is thr best information we have recieved to date.

No worries!

Canberra is its own council entirely (ACT Government), and Transport Canberra and City Serices (TCCS) owns the streetlights but hires a contractor to maintain the streetlights, the current contract is held by Omexom. I've previously reached out to TCCS about acquiring used streetlights, but unfortunately am not able to get them. I am somewhat in contact with someone from Omexom, but probably wouldn't be able to get one through him.

Try messaging Troy's Street Light Colection on Facebook ( https://www.facebook.com/auststreetlights/ ), he's usually quite generous with his lights and may have one spare.

Other than them, there's no other way to acquire one that I can think of, being a lantern from the 60s and 70s.

I've got metal hat off the top of one, and most of the diffuser, but it's smashed up pretty bad and is held together with tape.

FYI I've got an HW 877 (rebranded as Philips, but has the British Eleco part numbers) in my collection that you can view here. https://www.lighting-gallery.net/gallery/displayimage.php?album=7956&pos=35&pid=256961

Hit me up anytime for any other streetlight identification!

Hope this helps.