Hi joolijoo
Thank you for your post, it is vitally important that you make a claim for UC before your ESA ends, the same goes for mixed aged couples, it is vitally important to apply for UC before the eldest of a couple reaches state pension age.
If there is even one day between your ESA stopping and claiming UC then you will not get automatically placed in the LCWRA group, you will have to go through the assessment phase again resulting a loss of over £1k.
Seek advice from your local Welfare Rights Organisation before you do anything;
advicelocal.uk .
Gary