In a Laravel controller I have this redirect:
return redirect()->back();
Which returns me to my previous page (say http://domain/page).
return Redirect::to(URL::previous() . "#whatever");
And remember to import it at the top:
use Illuminate\Support\Facades\Redirect;
use Illuminate\Support\Facades\URL;
I hope this works for you!
You can use these helpers for laravel 5.5 and above - no imports :-)
return redirect()->to(url()->previous() . '#hash');