Hi Mark
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?
Regarding making a claim for mobility - you can put in a request for a 'change of circumstances' and tell them how your situation has changed. This will trigger a review and probably a telephone assessment.
BIS