I had not thought of that. But I feel as though that might be a bit too much effort when their must surely be a simple way of doing this - for this exact purpose - showing people how to use the Wiki on a Wiki.
I have figured out a solution that involves using the HTML code for squarebrackets. I tried it on the forum here when I was writing the above post but it did not work. Eventually I got tired of looking on-line for a solution and tried the HTML on the Sandbox Demo and it worked.
The HTML for a left square bracket is [
The HTML for a right square bracket is [
I am still keen to know if there is an 'escape character' for this. If there is not then there ought to be.
Thank you for the suggestion AL.