Working as an ECE relief teacher in Dunedin - how?

[Silver eye]

Hi everyone,

I'm British and have been living and working as a teacher (ECE) in New Zealand for 5 years now. I was living in Auckland but recently moved to Dunedin with my husband as he was re-located. I've been considering working as an ECE relief teacher but am confused about how it works and wondered if anyone could help.

I was expecting there to be a central agency for relief teachers but I've just figured out that teachers tend to approach ECE centres themselves and work directly with them.
But..... (And I apologise in advance for the daft questions!)

Can you register with more than one ECE centre? What happens if one rings you and you're already booked for the day? Probably a stupid question but I presume it's fine to say you're already committed elsewhere!

My parents are visiting from the UK later in the year, so I'm guessing i can just tell the centres that I'm not available for those weeks?

If I don't get along with a particular centre am I able to back out of working with them (for example a friend of mine who worked as a relief teacher in Wellington was able to tell her agency not to book her again with a particular centre after they treated her badly and she didn't like how they treated the children)....how do I do that as an independent reliever?

How do you get paid? I presume you give your bank account details to a centre. But has anyone had experience with it? Have you ever had difficulties chasing up a payment?

What happens about tax? Do I pay that myself with IRD?

Do individual centres usually ask their relievers to sign a contract? Does this make it harder to leave if you want to? For example if I want to get a permanent job. Incidentally, is there anyone who found a permanent job through relieving?

Sorry for the very stupid questions! I'm really tempted by relief work but there are too many questions about how it works practically for me to want to go ahead at the moment!

Thanks to anyone who can help!

Sliver eye.