Like you my car isn't type approved for towing (Picanto gt s) as I found out after buying the car.
l contacted many companies only to find that some Picantos of my year would take a non towing towball but not my model
I have a Halfords rear hatch mounted 4 bike carrier (£3 on eBay
)
but I’m only comfortable using it for short journeys, with two E bikes on it the straps loosen and I can see it moving around against my rear window, the bikes also obscure the lights and number plate.
I just came across this conversation,
https://www.toyotaownersclub.com/forums/topic/179314-carrying-4-bikes-on-auris-touring-sports-hybrid/
And PaulChen make some nice bespoke carriers that look a lot better than the universal fitment Type, personally I didn’t think ind use it enough to warrant the cost
Heres the PaulChen system for an Auris
Paulchen Fahrradträger für Toyota Auris Touring Sports auch für Hybrid Baujahr 2013 Juli bis 2019 Mrz., für den Transport von bis zu 3 Fahrrädern.
paulchensystem.net