I had my windscreen washer bottle removed as well when they installed my front mount.
Process west said there is no need to move it and others have kept it.
I had a bit of a go, got rather difficult since my wheels were tightened up way too much for me to get them off with the tools I had. It did fit back in place kind of
Im sure it would fit back as per usual with a bit more time and patience.
Out of curiousity, do the STi's still have the wiring in place for fog lights? Because I still have one plug left over which I cant find where it goes. The only place it loooks like it could fit was into the foglight.