Hi tony
Welcome to the forum, you might want to have a look at the following FAQ which explains where everything is
Welcome to Benefits and Work In case you are not aware, your real name appears to be showing in the forum, if you want to change this then follow the instructions in the following FAQ
My full name is showing, how can I stop it? You are correct in your first question, both parts of PIP will continue. As for the second question, you are correct in saying SDP will stop when your ESA stops but you may be eligible to apply for Pension Credit in which case if you meet the qualifying condition then you can receive a SDP with your Pension Credit.
www.gov.uk/pension-credit If you have any further questions, please come back to the forum.
Gary