I think it is a good idea to do classes through the hospital because you can learn about their philosophies/practises and see how these match up with your birth plans. It can also give you a chance to get used to the environment where you will be birthing.
I haven't done the course you are looking at, but have heard great things about the calm birth classes. Great idea if you can book in. There was a thread a couple of months back about Calm birth classes.
I ran a search and found these threads that talk about Calm birth classes.
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