treacle for example is similar to black molasses
When I looked that up, the best description I could find was that it was a form of sweet syrup. I was thinking it would be like maple syrup of Karo syrup. Molasses, though, makes sense.

mixed spice is exactly " mixed spices "- usually a mixture of ground ginger and cloves and cinnamon , but the amounts differ and there are variations, in the UK it's a very common every day spice available in almost every grocery shop.
That's great for general info, but how do I make it? Do you know the proportions of each?

I suppose it's a little bit like using "curry powder" which is a blend of a bunch of different spices, and there are a zillion different blends out there. It's easy if I can buy "curry powder" at the store, but if I had to make my own, I'd need a recipe of sorts. That's what I need for the "mixed spice", since that's not something I can buy here.

Scalding a cloth , simply means throwing boliing water over it to sterilise it!]
Ah, good to know. Thanks! But... what the heck is "pudding cloth"? Is it something like cheesecloth? American pudding doesn't have cloth involved!