That looks OK.

Get the whole website and search it all at once. Don't try doing it bits at a time on files you've opened. Textpad can search folders (demo).

Have you searched for "wagon" or "park" or "wagonpark" or similar?

.htaccess?

You can't get shell access? Would just be easier than using say Notepad++. If not you should be able to just FTP the whole lot off.

Is there an old backup of the website you could do a diff against (recommend WinMerge on Windows).