Warm home scheme

Hi my Mam is wanting to switch to bulb from another energy company but as she already receives the WHS if she does leave her current supplier to move to bulb will she lose her £140?
Also if not what does she need to do?

Does this page https://help.bulb.co.uk/hc/en-us/articles/115001245512-Can-I-get-the-Warm-Home-Discount- answer your query?

Please be carefull about giving any personal here, this is an open forum which will be seen by many.