What Car - 4-5k frugal estate

[BERGS2]

looking for inspiration.

kids stuff wont fit in either mine or the missus cars (1 series & C3)

need to get an estate for not too much cash to haul kids & the inordinate amount of crap we seem to have accumulated to transport them around.

criteria:

big boot for double buggy etc.
35+mpg
4-5k
not driving like a barge

VAG turbo diesel?

any mock 4x4?
anything else ?

cheers y'all