Unfortunately the arrival of a new machine coincided with a need to reduce caffeine so I have also been drinking decaf recently - so enjoying this question and the replies it’s generated. Thank you all.
My experience so far has been that good decaf is still good coffee, just missing something (obviously). It’s not like the analogies given as nothing extra has had to be added to make up for sugar/alcohol/caffeine, so there’s no need to try and match the flavour of the original with the substitute. I do find I love the way I can have as many as I want in a day.
As others have noted it’s necessary to grind finer and in my (so far) limited experience, two weeks is the minimum storage time before drinking. My kilo from Horsham roasters must have been over a month old before it was finished and some of the last cups were the best. But maybe I was just getting used to the machine 🤔 ?