How can I fix my Sherborne Large Henley Riser Recliner Chair?

I have a 2008 Sherborne Large Henley Riser Recliner Chair which has the Green LED flashing on the Handset. I have completed all the normal reset routines switch off main power etc unplugged all connections etc and the flashing green light on the handset remains. Anyone have details how i can reset something that removes the flashing light and allows the chair to operate as normal?
Mick cosby, July 2020