Richard, I used the exact items from my local Bunnings
Once I removed the 'black knob' collimation screws and replaced them with the 6mm x 50mm long screws, I then used the 'black knob' screws in place of the 'white knob' locking screws.
I should use a 35mm extension but I haven't had the chance to get to BinTel at this stage.