Hi guys, advice urgently required from anyone who has had this issue before, thanks in advance.

Recently purchased this car @ 136,000 miles with new timing chain fitted.
drove car approximately 20 miles, all seemed fine, plenty of power, though car was a bit noisy, even for a big diesel but I just put that down to the higher mileage.
the first time I attempted to put it under load and accelerated from traffic lights in first gear the car had a sudden loss of power and went into limp mode. Tachometer dropped to zero whilst still moving and then three miles down the road the car cut out and would not restart. The car turns over freely but it's almost like there is no fuel.
upon inspection we found no fault codes (possibly because I disconnected battery earlier), when turning the engine over we had no reading from the crank sensor, leading us to believe it could be a faulty sensor, upon further inspection we found lots of oil around the crank sensor area and oil is literally dripping from the bottom of the car.
I have contacted the seller and they are coming to inspect the car Wednesday but I'd like to have some idea of what the issue could be before they arrive.

if anyone has experienced similar issues after a timing chain / oil replacement I would be very interested to hear from you.

thanks again.