Will you share our joys?

We like the winter season so far.
We're just dealing with one room, the heating is on, the customers aren't in a hurry to leave so we spend the day making coffee and lunches, chatting and fiddling with the gift display.
There was one downside yesterday.
Three people came for lunch and sat near the window. I was pricing up Sophie Allport mugs and Heyland and Whittle soaps when I overheard one of them mention Ovaltine and the ovaltineys song.
My mum used to sing it around the house. It's originally from the 1930s but was used on an advert in the 70s.
I know all the words.
It is now firmly stuck in my head.