I can’t disagree Mikey, first time was worse mind you, at least it was dry and relatively warm this time. Last time was during the storms we had in February, so small mercies and all that

Should it fail again, words will be had with ECP about their product reliability. . Got - 2017 SDV8 Autobiography in Loire Blue
Had- 2008 TDV8 Vogue SE in Java black
Had - 2007 S/C in Stornoway Grey

With my CTEK if the charge doesn't progress past the last stage it means the battery is on it's way out. I think my charger has five stages and only charges to stage 4 but the battery performs without issue. If it is stuck more than one stage before completion, say stage 3 of 5 then that sounds like a new battery might be needed.

The manual for your specific CTEK should tell more and if you dont have the manual, you should find one easily on line.