Welcome to the forum Gill
I have a 6 year old GSP who suffers from a form of CLE. It effects mainly his under carriage, insides of his legs and underside of his neck. To date, only flaired up on his face/ears once (fingers crossed). He too has been off treatment for several years although, he is given doses of vitamin c at the start of the spring and this continues until october. I have also heard good things about Vitamin E, but have never tried it. Pollen seems to be a 'trigger', although as you know anything can trigger a response.
I am sorry I do not have any advice for you, but will be interested to hear what others have to say on this subject.
Incidently, my dog has just entered a 'spooky' stage.This is the first sign for us, that the rollercoaster is about to start
I wish your dog well.