Advice on buying a second hand 7 seater tow car

I have a budget of £2,500 and seek some advice on a suitable 7- seater second hand tow car. The van I tow is a 550/6 Bailey Ranger 2006, MPTLM 1378 and MIRO 1026. The running cost is essential even though the main function will be to tow the van. I quite fancy the Land Rover Discovery TD5 but would have to realistically settle for what I can afford. I'd be grateful for your advice. I currently tow with a VW Sharan 2.0 litre petrol which is quite sluggish. Best Kofi65