Whats it worth?

Buying a N plate 300tdi with 119k bodywork is average for its year, no crunch in 2nd 7 seater without sunroofs, towbar new tyres.
The window wipers kind of work and the door lock aint working but i can have parts from a 200 series which is breaking if i want.
There is a small leak on the passenger footwell and its motd til may,
it drives ok but having never driven a disco before i find it a bit sluggish pulling away, the turbo works.

£1400 is what im paying for it, is it worth it?

it may have the dreaded egr valve on the inlet/turbo side, this will hold it back on acceleration, they are not the fastest vehicle but once rolling they are great, just need a bit of getting used to. The price doesn't seem to bad, compare with ones on ebay and they will have loads more miles for usually more money.

what about the wipers and the door lock? is this common?

front or rear wipers? external door handle?

front wipers, door handle ok the drivers door lock just turns.

Seems a good enough deal, i payed 2k for a 96 (P) in good condition wi a few dings about it.
As said have a look on ebay or autotraders web site, that'll give you a fair idea of what's going for the money.