new to me land rover probs allready

Hi all I am a new Land Rover owner my whole life i have wanted one now i am in a position to own one...... first off 2 days into owning my 95 disco my idle started getting pretty high.. startup at 3000 rpm 2 secs later 2000 tthen 2 secs after that resides at 1100...... dunno why this is ......... any help....... next the same day in noticed this high rpm my enginestarted getting louder 3 days after that my exhaust pipe came completely off i booked in the shop this morning for tomorrow for a muffler replacement ,,,,, on my way home tonight i switched into reverse from park ... and low and behold i get a grinding and a clunk i put it back into park and try it again now it is just a klunk i am wondering if all or any of these are related and maybe some suggestions since i cannot get it into a land rover dealer for 2 mths
Ronnie

Have you checked the gear box and transfer box oil levels? my v8i auto clunks when changing from drive to reverse but had the same noise on other makes autos.