Error 402 CLI on Shopify dev account

Hi All,

I initially created a normal shopify.com account, and was able to get up and running editing via the CLI.

However after the trial ended, i realised shopify.dev exists - So signed up there with the same email address.

Ive logged out, and back in with the Shopify CLI - Created new stored under the dev account, but whenever running:

shopify theme dev --theme https://shopify-dev-site.myshopify.com

It opens the browser to login, as expected, but then in CLI it always returns [402] API request client error.

Its a dev account to create new dev themes etc, so shouldnt need any payment info.

Whats happening here? And what steps do I need to take to get the dev environment running correctly again?