Sorry, I sorted it, confusing myself over 2 days by reading 2 different sources of documentation didn't make it clearer :)
so the issue was. in Cashier you need to add the address with updateStripeCustomer before you do the newSubscription - this was why I was getting the same message
The customer's location isn't recognized. Set a valid customer address in order to automatically calculate tax.
here is the updated code
$user->updateStripeCustomer([
'address' => [
'postal_code' => $request->get('postal_code'),
'country' => 'AU',
],
]);
// Create a new subscription for the user
$user->newSubscription($request->plan, $plan->stripe_id)
->create($paymentMethod, [
'name' => $request->get('name'),
'email' => $user->email,
'payment_method' => $paymentMethod,
]);
hopes this helps some in the future :)