No 2nd gear in LT77

Hi all,
Have a problem with my 1991 200Tdi defender 90(Lt77). After using low range at the weekend when doing some greenlaning, I can no longer get second gear. All other gears are fine but second has no drive, there is no crunching before or after, only a quite whine when trying to enter 2nd gear now. Could do with any advice available?

Is it going into gear and not driving? or is it just not possible to select the gear? Your post does not make this clear.

Sorry it goes into 2nd gear/position and doesn't pop out into the normal neutral position