We've got a similar issue: looking for a Bongo replacement to take 4 people, bikes and luggage around the country.
Our initial thought was RS6 avant or E55 estate but neither of which can fit a tow bar apparently due to type approval

X5s, Cayennes, Touaregs and XC90s were next port of call but they're surprisingly small inside. A Cayenne Turbo may be more sensible than it first appears as they avoid the nikasil lining issue which affects the S engine.
Started looking at Discos and soon realised a L322 TDV8 Range Rover was a far nicer experience. Fear of big bills and £550/yr tax seems to keep the prices pretty low.