Thanks Deeps. I ended up disconnecting the non-power cables coming from the Material Station. I then ran the filament from a stand alone spool holder for convenience, rather than attempt to reinstall the spool holders on the back of the S5. I received warnings about the NFC spool not being connected (normally I guess this is overridden by the Material Station connection), but the print ran OK. I agree that this is annoying. However, once you've reached the back of the printer to access the feeder anyway, unplugging the Material Station is not really too much of a pain. It would certainly be nicer though if there was what appeared to be a 'supported' solution to doing this in the printer UI, rather than needing to unplug stuff.