Hi LittleC
When you apply for UC you should migrate straight over to LCWRA element of UC providing there is no break in your ESA claim.
What sometimes happens when you migrate over, DWP will send you a WCA review form, they can send these at any time, you will still continue to be paid LCWRA element until a new decision has been made.
Gary
Nothing on this board constitutes legal advice - always consult a professional about specific problems