Ok so had a check, photos confirm my old S1 had an Odyssey PC-925 which was AGM, new battery in the GTN is a Full Throttle FT410 PC925 also AGM.
Interestingly the old S1 battery I think reading the sticker albeit not entirely clear was dated 2008 (casing manufacture I believe so guessing 08/09)! The new (suspected troublesome one) is 2022...not sure if thats luck or just speaks for the quality of Odyssey!
