Eben: For what it's worth.....there's a company down in Sydney NSW called Bryburn Trading Company, who is listed on Ebay as 38margate. This fellow has a abundance of Vickers Parts and accessories and over the years I've bought a number of items off him for my unit. He may have what you need (I don't think he's cheap) but given what Chris has suggested and Lynn has brought up, you might want to contact him to see if he may have what you want. Lynn's right about the importing of "parts" and you should do your homework if your considering buying off shore.
AND if push came to shove....I have 2 WW1 tripods here that I can take measurements of for a repro. AND NO THEY"RE NOT FOR SALE! You're probably looking at $800.00 to $1000.00 US for the real thing on this end plus shipping, if you can find them, which is once in a blue moon. Hope this helps......Robert
PS: I write this enjoying a glass of your "Yellow Tail" Moscato white wine. (recommended) God ....you guys make nice wines!!!