Yes, you're in Bristol. That suggests to me that what the OP is suffering from is more likely SE drivers syndrome, rather than small car syndrome. Over 50 years of driving all sorts - from motorbike to HGV - and I'm convinced that once you get north and west of the M25, the driving improves the further you go.I drive a mini in an out of Bristol every day and have done for 5 years. Was a Seat Ibiza for 7 years before that. Never had a problem being bullied. And Bristol is a traffic hellhole.
Never noticed any real difference in bad driving manners due to the vehicle being driven, but I did notice on motorways there were some drivers who just could not bear to be overtaken by an old 998cc Nissan Micra, and would come roaring back past as soon as they'd been overtaken!