collars

Does anyone have the 2 collars (that go in the seals either end) ? (part 3 on drawing) Or just the dimensions so I can cut a pair.:bang head: This is where I start to find all the little bits'n'bobs that are missing.

I have a 1991 VMax that I'm replacing the downpipes on (rusted original one) and I have run into some trouble. I'm running out of ideas so any thoughts would be appreciated. Out of 4 studs, the first one came out with the hex nut (probably the best possible outcome), the second sheared off...