removing the middle seat in my 110 today i accidentally hit it into hi difflock,what a bastard it turned out to be to get it out again, had it in difflock a few times no issues just reverse it to get it out,is the linkage easier to get at on a defender? its a 300 tdi with R380,does it just need greasing? like in this vid https://www.youtube.com/watch?v=6H0AM-SXwSY

I had the same problem last week. Accidentally knocked it into diff lock. Ended up having to remove the centre tunnel and free the linkage. ( my 90 has been standing for 5 years)
I also gave the switch a tap in case it was stuck and showing that it was in diff lock when it wasn't. The centre tunnel screws were seized so a tap with a flat screwdriver between the head of the screw and the washer helped.
Is the vehicle definitely in diff lock or is the indicator showing on the dash? Might be worth jacking a wheel up and putting it into gear and carefully let the clutch out to see if it makes any attempt to move. If it's not in diff lock, it won't move and only the jacked up wheel will turn.

its out of diff now,lights out,not fun turning left or right sharply in diff

I,m afraid to put mine into diff lock again to see what happens. I,ll leave it until I go to my mates place next week. He's going to give it the once over and check that everything works as it should. Pretty handy guy to know, been keeping me right with all I've done. That is along with the advice I've received here. Tbh, really enjoyed working on the truck. I,m more used to working on Minis were everything is small and diddly, landys are more accessible for my big sausage hands.

You naughty boy! You haven't been using difflock hence it automatically means that you haven't put your landy through its paces