CitiGos are great & very capable - I drove my mum's to Croatia & back plus a lap of the Nurburgring. The higher power versions even have a bit of kick (though that might just be because I'm used to driving a base spec van). Also somehow if you get the right version it's zero VED.
Love that you lapped in the 'ring in one! They handle great, although the gearing is very much set up for motorway crusing so always found it a bit flat. I think the rarer higher power model is just an ECU tweek away - same engine etc. Shame it never got the TSI like the Up!
We really liked our 5dr CitiGo but I think the auto version is trash.
I think you'll be fine having her as the second driver whilse she's a learner.