Hi Mick
We have had a few inquiries similar to your this week, unfortunately the answer is the same. When your IR ESA stops when you go over the savings threshold, you have to start the claim from the start.
Unfortunately IR ESA and CB ESA is no longer available to new claimants. Those who used to claim IR ESA will now have to apply for UC, to get the LCWRA element they will have to provide a 'fit note', they will then receive a Work Capability Assessment (WCA) form called a UC50 which is the same as the legagcy benefit form ESA50.
If you kept a copy of the original application then you can use that as a template for the new form.
In answer to your second question there is a TAB at the top named UC, when you click on it, it will give you details of claiming the WCA, if you want information about claiming UC then the Gov web site has details;
www.gov.uk/universal-credit/how-to-claim or Citizen Advice
www.citizensadvice.org.uk/benefits/unive...or-universal-credit/ , there are others if you look on the net.
Gary