I've not really found the Octavia small but before I started using Octavias in 2004 I had a diesel Astra and before that a couple of jap import diesel corollas... so the Octavias are decidedly spacious for me! However, they do put a lot of space in the boot which obviously takes from rear passenger accommodation space.
I've never used or considered a petrol car as a taxi, Ken. Over the years there's probably only 2 fully fledged petrol cars that would stand out from a durability perspective. The first was a Datsun, the name of which I can't remember and the second the Toyota Carina E. Toyota Hybrids are noted for high kilometreage so that's where I would be looking before any petrol car. I didn't know the Camry has been discontinued. I'm not one to offer advice but maybe you'd be better served by a 2/3yo Camry, perhaps directly imported from Japan? I would also suggest caution if buying a Jap import locally. Toyotas are notoriously simple to clock... in fact, I think the bauld Stewart kessie reported being stitched up by a used car importer, if memory serves he found the auction sheets (with actual kilometreage recorded) in the glove boxes or on tinternet or some such.... ifn he can be had, anyone can I guess!