Like you, I thought that not only was EU/EEA cover normally included but, more comprehensively, it was now standard via EU legislation/regulations. I say this without being absolutely certain but whenever I have insured a vehicle European cover has been included without me requiring to arrange it. On the other hand I think some UK insurers may have in their terms that one should notify them if planning to go abroad but if the cover is an EU requirement then this would not be crucial.
If you have anyone you can get to contact Citizens Advice, or similar, and enquire for you then I suggest you arrange that.