From what I understand, the vRS MK1 and MK2 have OBD2 connectors....

 

Now that I've purchased Torque Pro and an ELM bluetooth OBD2 Reader for my MG, I was wondering if the O3 also has one? (If the Citigo has one too, bonus!)

All modern cars have one, it is under the steering wheel on the right hand side.

Same place for the Citigo too

I can confirm Torque Pro and an ELM bluetooth adapter work on the O3 - I bought one last week, not had time to play with it just yet - but it's awesome. 

 

My only regret is I should have tried cabled - as it prevents the phone from connecting via Bluetooth to the O3 Headunit for phone use :(