\\\\ Does anyone know whether, if this recurs, I could take an extra Sotalol (an anti-arrhythmic and beta blocker) tablet to try and control it.\\
Yes you can as a one off, as for example last night, which was presumably due to the excess alcohol. If of course , you were still experiencing rapid pulse and ectopics this morning, then you should seek urgent medical help.
As your pulse is now normal, then you have "got away with it."
So yes, you can, as a "0ne off."