Land Rover Repair: LR Disco 95 3.9L, ok tank, head gaskets

Question
hi, we just had my wife's Landie repaired (cylinder heads skimmed and new head gaskets). When we got it back it revved at about 1750rpm. Took it back to local garage and they sort of corrected it but after getting home, Landie won't start. It cranks healthily but won't fire up. Spark looks OK, tank is full but fuel stream not very strong. 233,000km on the clock and fuel pump replaced at 187,000km. Could it be a sensor or the fuel filter that's dirty?

Answer
So here's the situation  . . . you had new head gaskets fitted, and now the truck idles too fast.  What's the connection between those two events?  I doubt if it's in the gas tank.  More likely it is something under the hood.  Look over that work carfully and you will probably find the answer.