It should always create the shipping fields as long as that checkbox is checked, the checkout form you have seems to be what would result if that checkbox was not checked.
I'll double check that. I don't recall that checkbox but I don't doubt it's there!
SagePay have confirmed that the original URL the eCart used, https://test.sagepay.com/Simulator/VSPFormGateway.asp, is no longer in use.
HTTP Status Code: 500
HTTP Status Message: The request was unsuccessful due to an unexpected condition encountered by the server.
Error Code : 3098
Error Description : The VPSProtocol value is not supported by the system in use.
I'll contact Sage Pay again and find out which URL is correct.