What are you buying? A Mercedes Benz?
I shipped mostly everything i ever sold here through the german Post and their package service DHL. They never said somthing about the size. All they do is weigh the package and sometimes they tell me ugly prices.
On their website they state the package for international shipping can have the dimensions up to 120cm x 60cm x 60cm and up to 35kg weight.
Alternativly the seller could use Hermes. Shipped some things with Hermes to the US never had a problem. They do even bigger packages.
If it is a bike that you are buying maybe you want to consider to tell the seller to send it in two different boxes to keep weight and size down. That way there is some money to save.
But what bike weighs more than 35kg? Now i'm curious...
I hope that all helps a little.
been talking with the guy about postage but now it seems he's not too sure the front triangle is safe due to rust , not to worry , much better option reared its beutifull head thanks to a forum member