I haven't yet experimented with grille blocks on this car, but I reckon the top grille is largely cosmetic. Unfortunately I have not yet found a way of getting "live" mpg with this engine.
A diesel should not need any cranking, well not beyond 2 revolutions maybe, so if you're having to crank its a bad sign - and on this engine you might find that parking uphill, or with a low fuel tank, it gets worse. Leakoff pipes are the culprit. See this forum post:
2.0 and 2.2 Dti Diesels all models no start