I think I've installed 3.1.3 using composer (I'm not sure how to check which version I have installed) using
composer create-project silverstripe/installer ./my/website/folder
Error: Syntax error, unrecognized expression:
I'm guessing there's something wrong with Sizzle/jQuery as the next editing screen doesn't appear.
If I refresh the browser I can see the newly created Page in the Pages list and edit it