Despite feeling like a huge car, the current Passat has less boot space than our old Focus estate, so would be much less than a Mondie.
We moved up to an S-Max too. It uses the Galaxy floor pan, but has 3″ less head height at the rear.
But for your budget, I would be looking at the Alhambra as you get a bit better for your money than the other two. Sharan’s the least.
Then again, there’s tons of Galaxy’s about though, 7K can see you in an 05 plate 1.9l diesel, Ghia, with around 65k on the clock.
Make sure the aircon works, and check the aux heater if fitted, these are known to be very problematic.