Absolutely agree they are very helpful;
also be careful to check the certificate when it arrives, our renewal certificate was stamped but not signed but replaced within a few days after a quick phone call,
The SSR team in Cardiff are really helpful and friendly. New and re-registration is made straightforward and costs and can all be done on line. However, make sure that you check and double check everything you send them. De-registration is free. One gets a 'transcript'.
It costs £35 (2019) initially and the same amount for changes. It takes 2 - 5 days for the documents to be sent out.