What questions should I ask about private orthodontist quote?

[MrsFogi]

Dd needs a brace etc and we could wait 18 months or go private. I have put her on the waiting list but have also got a quote in case we decide to get her teeth done privately now. Can anyone suggest any questions I should raise before signing up to private treatment (so far I think I need to ask about whether or not the retainer is included (I suspect not), whether breakages are charged extra).
Also is there ever any room for negotiation on the quote?

Has no one asked any questions (or wished they did) ? thanks

DS had his on the NHS. I wish I'd know how often he had to attend for follow up and whether appointments were available after school.
I suppose you could also check that all the treatment including X-rays is included in the quote.