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There are two potential elements to alcohol labelling here.
The 1.2% threshold applies to alcoholic drinks - in accordance with Article 9(1)(k) of Regulation (EU) 1169/2011, these are required to include an indication of the alcohol content, as detailed in Annex XII of the same regulation. This is separate to any considerations relating to the ingredient list, as these products are exempt from the requirement for an ingredients list. If you're making some sort of composite food product with an ABV below 1.2% then this requirement will almost certainly not apply.
Separately there is the question of whether alcohol should be declared as a component of a (compound?) ingredient in your ingredients list. This is very much going to come down to the specifics of the component in question. There could be legitimate exemptions where, for example, the alcohol is an inherent part of an ingredient with a defined legal name - for example, if you use whisky in a filling for a chocolate, I suspect it would be acceptable to simply declare it as whisky, rather than having to provide a component breakdown, particularly given that alcohol itself isn't actually an ingredient of the whisky.