Gear selector issue

Folks I've had my TD4 sport Freelander 1 for about 6 months, yesterday on my way home i could only select gear 3 or 4..... no 1st, 2nd, 5th or reverse. I've checked the linkages and all are intact. Suspect there's an issue where the linkage connects to the gearbox.... any idea where i could view a diagram of this area to see if something is broken or missing

If you look under the car there are two metal linkages from the gearstick to the front firewall then two more linkages connect from the firewall to the gearbox. One moves when you push the gearstick left and right and the other forwards and back.
They just pop on and off ball joints so one of them has popped off.
If you drive two wheels onto a high curb or jack the car up and slide underneath it should be obvious.

If you're lucky the linkage will still be there and will be easy to pop back on. If not.......

Linkages are all connected though it looks like there's something broken on the linkage that moves the gear lever left and right.... I'm able to move stick inside the car with movement showing at the gearbox and vice versa but the linkage doesn't appear to me moving anything inside the gearbox

So what you're saying is that with someone in the car moving the gearstick side to side the linkages all the way to the gearbox are OK and the lever on the gearbox is moving too but the gearbox only selects 3rd and 4th.
That sounds odd, I've never heard of a gearbox fail like that but I'm no expert.
I have heard that the linkages can become loose and cause issues but haven't seen it myself.
Are you sure it the lever on the gearbox is being pushed far enough to select other gears? If the car was on 4 axel stands you could manually push the lever with your hand to see what happens.