You are doing fine
Lexus do a stand-alone hybrid test (I think it costs around £90) which would give you peace of mind in relation to the check hybrid light.......a successful test then gives your hybrid battery a year's warranty - although I see it states it is for vehicles 'up to 15 years old', so you may want to book it in soon...replacement hybrid batteries are an expensive item, so if it were me, I would get a check....
See here:
https://www.lexus.co.uk/owners/servicing-and-maintenance/servicing-mot-hybrid-health-check