Passenger Backrest F3LTD

A friend of mine wants to extend the height of the passenger backrest on his 2019 F3LTD
His passenger has a medical condition and needs the backrest to be higher by about 3” to 4” and across the width to give extra support
The issue is that the Rear Trunk Lid opens over the existing passenger backrest
Has anyone modified the backrest to allow this to be done or can suggest a work around to achieve the desired result