In Simple solution for an online read-only TW, @Charlie_Veniot provided a simple way of hiding editing buttons in the TW UI. He gave a simple stylesheet which seems to hide stuff very well. Recognise though, as stated in that post, this is not a true read-only wiki, it just looks that way.
However, on using this in the current version of TW, it does not hide the edit nor more button in the tiddler display.
I looked at the elements involved and saw that these two buttons were not included in his stylesheet. So I added them and it seems to hide these two buttons as well.
The new stylesheet should look like below, with the addition of
[aria-label*="Edit"],
[aria-label*="more"],
My first foray into the TW UI … frightening really 
bobj