Broken Theme In Dashboard

Hi,

Firstly great theme love using it!

I have come into some problems with the theme however. I have disabled all plugins and switched themes to the default theme and there are no problems so it is 100% with the theme.

Basically when you go to the dashboard or try and upload a plugin or edit a theme or add a page. I keep getting this error:

Warning: call_user_func_array() expects parameter 1 to be a valid callback, first array member is not a valid class name or object in /home/nothingbutdev/public_html/2018/tomcheesewright/wp-includes/class-wp-hook.php on line 286

Any ideas?

Front end is fine – no issues when you view the site.

Thanks again
Greg