Thanks for the advice again, Declan.

I also rang up some other people in the same line of work and discussed it 
with them, and their advice was actually to just send off "whatever" and 
hope that they didn't refuse it, the theory being that if they did refuse 
it, then they would say exactly what they wanted.

So, armed with the advice, I went down to the local hanko shop and ordered 
two seals, one with my katakana name on it, and another with my prospective 
company's name in katakana. I ordered the cheapest ones (about 3,000 yen 
each) and then if that doesn't work I have to buy a "company" type seal 
which costs about 25,000 yen.

Once I have the seals I'll go and register and make a bank account with 
them.

Let's hope it goes well.

Danny.