Well the Plus8 best for me is around 23 checked on actual fuel used between tank fills. Reading Alistair's I'm quite pleased

.
The Polo 1.8 GTI gets 27 driven by my good lady, I very much doubt this was the VAG official combined figure.
The 1.6 Diesel Fiesta gets 60 provided you keep it legal so I imagine that's pretty close.
All checked tank fill to tank fill you can't rely on the car computers I've found, especially the Morgan one

.