rear wiper arem replacement estate

[johnny the fox]

hi, my rear wiper arm started to drop. I took it off and it clearly showed signs of wear! I located a replacement via the internet. when it arrived i could see that it wasn't the same due to the fact it has a brass centre. my spindle on the car has a steel type bulbous centre with a rough edge and you just push on a replacement and it grips it. I informed the seller that his replacement was not correct. his ad states that it fits all models 02-08. I have spoken to him but he is still saying that I must still have a piece of the old arm still stuck on the spindle preventing the new arm from going on. I have examined the spindle and cleaned it up and there is no way anything can be removed as it is one piece. has anyone with an estate experience this? or can tell me does the early mk11's have a different spindle to the later face lift model, thanks johnny.