Apologies if this comes across as a rather long winded one... The decision isn't an easy one, hence a simple bit of advice would be most gratefully received!

My growing family, currently myself, wife, 7 & 4 year-old boys, Labrador and perhaps baby addition, are looking to swap two cars for one, and there are several, hopefully not mutually exclusive, requiremens to meet...

The two cars to replace are an Audi a4 avant, and a jaguar xkr coupe. Between them we have practicality and reliability, through to performance and driving enjoyment. As a family most driving is urban, with longer trips thrown in. Yearly our mileage isn't that high so whilst economy is a consideration, it's not the primary factor.

The two car types we are tending towards are SUV or mid size bigger engined estate, so would someone care comment on the shortlist if they have any experience of the proposed choices we have?

Audi; fancy an rs6 but is the practicality/enjoyment totally negated by the huge fuel costs it would require?

Alternative a Q7, like the idea of 7 seats, but is it simply too large? The best engine choice is probably a diesel I'm thinking?

Mercedes; again the choice between an e class (heart says e63- The last model had 7 seats?) or the M-Class SUV, which if I'm honest isn't a big contender.

BMW; the new F10 5-Series touring, can't find any confirmation if there is a forthcoming m5 touring to hold out for, or again, the X5 appears to be a very useable car, probably in diesel guise..

Lastly, the Porsche Cayenne. The appearance has improved and it looks to be a very sturdy contender, be it the diesel or "S" model.

Apologies once again for what is a very broad swathe of questioning, but after two garages (Porsche and Audi) the choice is seemingly harder, and far from impartial when you do ask the sales rep. When you mention the shortlist , said salesperson then proceeds to spend more time denigrating the other makes than promoting his or her own!