Hi, I have a detachable towbar that was fitted by Landrover. I haven't had any problems with it until today after my wife towed a heavy trailer with it and I'm now unable to get remove the detachable part. It has a twist lock on the side (with red & green indicators, plus a key - that is defintiely unlocked). I normally push the lock in and twist downwards and the hitch comes loose. At the moment the twist lock won't quite push fully in so it won't allow me to turn it fully to detach it. It is definitely unlocked though as if I turn the key then it moves even less.

Any tips or advice, or am I going to have to visit a dealer?

I would visit a towbar fitting company, they might have more idea than a dealer as they may have come across it more often

Mines fitted style so don't have any other ideas that don't involve hitting it with a sledge hammer  Former Mod/Member, with the most post & Chicken George Arch nemesis

Npinks, your spot on with the prescribed method of removal. , try knocking the tow bar in/ up into the housing( heavy trailer pulled it down/ out) this should return tow bar to normal position. Then blather wd40 all over the lock and pin, then rotate the green knob and bray tow bar with a good sized hammer, 4lb lump ideally . My11 freelander 2, xs, Manual, 18" hse sparkles, sidesteps, privacy, zermatt silver metallic, almond nutmeg alacantra, twin electric towbar

Gone my09 xs D3

This was sometimes a problem with my detachable and it is caused by lack of lubrication to the twist lock mechanism. If you turn the locking nob by hand and then tap it gently with a rubber or wooden mallet to get it to go in you then may have to use grips or suchlike to twist it to the unlock position.
It will release, trust me, once off make sure you get plenty of silicon lubricant inside the twist lock mechanism and the pawl on the bar itself.
You will not have any problems thereafter. Ralph
Zurmatt Silver, Diesel, Automatic, side steps, mud flaps, mats, boot liner, TomTom Start 60 installed, rubbing strips, removable Brink tow bar, after market tinted glass, front styling bar, Rear spoiler, Motorlicious tail pipe trim. Wood Company centre armrest