The selector wont move or the trans wont engage when the selector is in gear? Those are two totally different problems.
So can you move the shifter? If it (the shifter) goes into gear and there's no drive and you're SURE the CDL is whereit should be, then im not sure where to go from here

 

As you can see, if you have not been having any problems up until now, the no go either direction points to that short shift lever that controls the transfer case. It can be very stiff to operate if not used very often. Time for a male friend with strong hands (not an issue with your gender, just this can be a hand strength issue, especially if rusty). When moved to various positions it controls the top speed of the vehicle (very slow for climbing or normal for driving), and regular or "locked" all four wheels try to turn at same time. That mode turns on something that looks like an "H" on your instrument panel. OK to drive in locked mode on dirt roads or beach, not a good idea on dry pavement as you make tires wear out very quickly.

It is unusual for a transmission to stop out of the blue, and even more unusual to stop for both directions. Some transmission shops offer "free" towing, it is built into the price.

Also, if the transmission shift lever won't move to "R" or "D" there can be other issues that are electric, part of the shift/ignition interlock system; that keeps you from engaging gears when you should not. Those kinds of issues would be dealt with by a general mechanic who is Rover savy. There's always the dealship, it will be your highest priced labor rate, but they do tend to get things fixed without a lot of head scratching.

 

If I'm insulting your intelligence, please accept my apologies. That is not my intent.

The CDL is the 'small' shifter, in front of the 'larger' shifter.

You have told us that you can hear the trans shifting when you move the large transmission shifter from P-R-N-D-3-2-1. OK.

If the CDL (small) is in neutral, the transmission will not be connected to the wheels and no power from the engine will pass to the wheels. So if your CDL is in neutral, nothing will work. They can be rather easy to knock out of gear.

With the main (large) transmission in neutral, try to push the small CDL lever toward the passenger seat and back toward the rear of the car. If the CDL is engaged correctly, and you still have no power to the wheels, we need to look at something else.

 

Where do you live Robin?
Maybe somewhere on here is close by and can give you a hand.

 

Follow Turf63's instructions. I wouldn't be surprised if this is nothing more than the transfer case slipping into neutral.

 

I've had this issue twice before. First off check everything aforementioned... second, check to see if your brake lights are working. If not, the issue could be your brake switch. It is located above your brake pedal and below your steering wheel. They'll run you around $100. If your brake lights are operating correctly, then go ahead and pop the cap off your main gear selector (the large one). Mine is wooden, some models are equipped with black plastic ones depending on your year and model. A flathead screwdriver should do the job. Once you pop that cap off you should see your selector shaft, and there should be a little c-clip around a groove at the top of the shaft. A few years ago my truck got stuck in a walmart parking lot with the same issue you're having. $250 later, between tow costs and 3 days of mercedes dealership mechanics scratching their heads, it ended up being that little c-clip. Which will run you about 50 cents at Napa and 30 seconds of digging into your vehicle. Hopefully that's your issue! If not, the brake switch isn't too difficult to replace. It's just f****** expensive as hell!!! Best of luck to you

 

so, what happened on this Robin?