UPDATE: Everything is fixed now - if you are a paid member you should be able to download for free.
If you are a paid member having difficulties downloading the project from the site for free, fellow subscriber Ralph has tracked down the issue Thanks Ralph!
Switch the currency at the top right of the screen to £GBP and free downloads should work immediately.
I’m working on fixing the problem permanently but in the meantime, this stop-gap should keep you going.
Thanks again Ralph!