R750 per month fuel saving? I think there is something horribly wrong with your Panda if she can save that much by changing over to the Figo.
Assuming 40kms a day during the week and 80kms a day on weekends (a rough thumbsuck) that means she'll do on average 1440kms a month. The combined average fuel economy for the Figo 1.4 TDCI is 5.3L per 100kms (taken from
here), so she'll need 80.64L of diesel a month. R11.19 per L of diesel inland (taken
here) means total fuel cost a month is R902.36.
That means average petrol spend on the same distance in the Panda is roughly R1650. Divide that by the current price of 93 in Gauteng (R12.24 from
here again) means you use 134.8L for the same commute distance in the Panda Young, a fuel ecomony of 9.5L per 100kms, MUCH higher than the claimed economy of the Panda young (5.6L per 100kms according to
here).
If your Panda really uses that much juice, I'd have it (or your wife's right foot) checked out.