Well spotted Hugo.
I think the clue is in Ind Coope. The building at the junction of Riviere's Avenue and Clarence Road in Craig y Don was, as you and Brian refer, better known as a bottling stores for Ind Coope. I don't think ale was ever actually brewed there. The building has now gone and unfortunately it is not possible to compare the photo with the actual but the balance of probabilities suggests it is the place. Probably Ind Coop acquired the site, extended the facilities and moved from 1 Mostyn Street. I recall they had a retail outlet in Clarence Road which later moved to the Washington Hotel (along with their offices).
The only other "ice" place I can think of is the Llandudno Ice Company's premises in Builder Street. That eventually became the Welsh Coast Ice Cream Company - older readers may recall "HiHat" ices!
I expect the advent of freezers meant demand for commercially supplied "pure ice" ended.