Buying replacement tubes online?

I recently got my new hearing aids ( Resound Key 3, KE377-DW ) from eBay, and I’m happy to say they work well and help a lot with understanding speech. I was talking to a friend whose voice I struggle with a lot, and I only said “can you repeat that?” maybe half a dozen times in half an hour. Absolutely magic, and I’m over the moon.

However, the tubes (size 2b) are too long/go too deep for my ears, and I need to buy shorter ones. (I assume I’d want 1b?)

I get the impression most DIYers just get theirs from their audiologist, but do you know of anywhere online I can order from? Ideally in Australia, but anywhere that’ll ship here is fine. It’s really hard for me to get around due to being physically disabled, so I try and do things online as much as possible.

Thanks for your help.

(Also yes, I’m aware my audiogram looks too good to need/benefit from hearing aids. My doctor is pretty confident I’ve got APD- which can be treated with HAs- but said that the process of getting “officially” diagnosed is very expensive and takes a long time. Still working on that. In the meantime she said that if I could get HAs that were programmed right, I’d probably benefit from them a lot, so… here I am )