Yes, for Pro: £450 once, or 3 payments of £150 (£450 in total, the same price), one payment every 4 weeks: the first at checkout, the second 4 weeks later and the third 8 weeks later. It's one purchase paid in parts, not a subscription, so you agree to all three payments at checkout.
The course is released in stages as you pay: the Starter edition after payment 1, the Builder edition, the group and your first call after payment 2, and the Pro edition, the done-with-you setup and your other two calls after payment 3. If a payment fails you have 7 days to fix it, and support and calls pause until then.