The first thing I did when I realized I needed the part, even before I spoke to Studio Spares, was to contact K&M via e-mail. Their representative was quick to respond. He was able to identify the correct part and give me the relevant reference number, even though his first language was German rather than English. He also recommended that I use the same dealer I bought the stand from, even though I'd asked to purchase it directly, so my thinking is that they don't deal with the consumer as a company policy.
As for sourcing it from another dealer, I think that's a great suggestion, and