I'm considering buying a second hand Peugeot 308 SW (2014/2015 model). I drive 500 miles a week to work and back on A roads. Whilst diesels do better mpg, it costs more to fill up and the prices to buy are more. I am also worried about the DPF and associated additives will cause expensive problems in the future. However, the diesel has a bigger engine for the family camping trip (two adults/2 children plus kit) so will be better for carrying loads?

Any advice or pros and cons to split the choice between petrol and diesel would be much appreciated. I assume it's a myth that diesels last longer than petrols as long as both are regularly serviced?