Russ,
Sorry to have begun a lot of confusing info for you by describing my own situation. I was in the middle of buying a horse for my adult granddaughter, and had two conversations going on at the same time. Dont worry, I never bought the horse online from the USA, and I wont have to pay any tax on him, although he is a young American Standardbred.
Anyway, Ill now focus on what I was trying to convey to you.
Basically, from what Ive seen lately, Western European CBA accordion prices are considerably more expensive than over on your side. Unless you can find a private UK seller, youre not going to get one below the prices on the links I posted.
I dont know what price you are looking at , but this firm in Nice (which has a major international airport) has a good reputation in France, and as you can see, they have one of the most varied ranges available. You might be able to persuade them to ship to USA, but as has been suggested elsewhere, with a selection like that you might want to go over there and try some of them out.
http://www.accordeon-sud-est.com/accordeon/accordeon-convertisseur.htm
Occasion means used, pre-owned, or secondhand, whichever you prefer. You may qualify for a 20% discount on the purchase price as you will be exporting it to the US, but youd have to discuss that with the retailer.