Even a totally fcuked 200 will start on the button as great engines.
Both my 200 have the fat breather pipe routed to atmosphere and the hole in the inlet trunking before the air filter blanked off, weirdly now they breath to atmosphere they dont seem to chuck much carp out at all?
Both used to chuck oil into the intercooler and its pipework all the time, now they are pretty much dry.
The blank is 3/4 of an inch inside diameter and cost about a fiver from ebay, got to be worth a try before shelling out on a turbo?
Iirc the defender 200tdi turbo is about twice the price of the disco version as its rarer.
Might be worth adding your approx location that way someone local might have a look for you, do not use your postcode for obvious reasons.