Hi SteveLilley ,
Apologies for any inconvenience caused.
Would you be so kind as to check the browser's console while it says "installing" and tell us if you can see any errors there?
Also, check the PHP error log and paste if any errors were logged while trying to install.
If you don't know how to activate the error log, please read this.
If you don't feel comfortable sharing your server info here, please open a private ticket.
Best Regards,
José Andrés