I suspect you will have to take the wires out of the plug before you can pull the loom through the hole in the Fender. There are soecific pick type tools to use but it is possible to use a small screwdriver or pin. There are different types of plugs and removal is slightly different for each one. Google/YouTube will have plenty of Vids. on how to do it.
Forgot to say, take picture of the Plug with the wires in situ before you remove them so you know where to replace them.