How about changing the battery to cope with your usage? I have changed to an Odyssey battery on my 97 Thunderbird - brilliant. Have not had to worry about charging for the last few years with it. Got it from Carrot Cycles in Lincoln - they deal with classic brit bikes rather than modern Hinckley so should be able to advise better for you. They advertise in the TOMCC Nacelle magazine.
I wish my T140D had electric start ;-) Personally, I would not de-S a T140ES.