Cracking little car, a real future classic.
"it would be illegal to fit a tow bar to a car not homologated for it"
No it wouldn't. It would be illegal to tow with it but if you had one fitted for a tow bar mounted bike rack there would not be any issues. I have a fabia vrs which was not homologated for towing like the normal fabia, there are plenty of them about with tow bars fitted for bike racks.