really, do them yourself. Unless you can make 2500 in a day, like the repair people are doing.. Although they are taking less than a day...
I did the head gaskets on my disco 1, as well as other vehicles I have had and can say that every time I did it correctly, and every time I thought the task would be soooo daunting, even if I have done the same type of car before, but they always suprise me with just how easy they really are.
It's a nice thing to look at your pistons and cylinders. Just to know...