-        filesize_approx = float_or_none(self._html_search_regex(
-            r'<p>\n<strong>Filesize:</strong>\n\s*([0-9.]+)\s*megabyte</p>',
-            webpage, 'filesize', fatal=False), invscale=1024 * 1024)
+        filesize_approx = parse_filesize(self._html_search_regex(
+            r'<p[^>]*>\s*<strong[^>]*>Filesize:</strong>\s*<span[^>]*>([^<]+)',
+            webpage, 'filesize', fatal=False))