On my newly purchased Freelander 2 there is a detachable tow bar but the ball part appears to be seized, I have tried penetrating fluid to release it to no avail
It is a landrover part but can I buy the detachable unit separately or do I have to buy whole towbar?

Try PF Jones they might, is it a LR bar, if it's a Witter or Brink you might try them direct.

Richard FL2 07 TD4 GS Auto
Ex 02 TD4 Auto

I diligently replaced the lock mechanism on mine, carefully cleaned and lubricated everything, reassembled, tested. All was good. I cleaned the receiver on the car, inserted the tow bar and....

It jammed in there.

I can only assume I didn't get all the dust and crud out of the hole in the receiver that the locking pin goes into. I have it on my "to do" list to apply lots of penetrating oil and some percussive persuasion this weekend. Current driveway contents:
2021 V60 Cross Country B5
2009 FL2 dog bus and shooting wagon

On Order: 2023 Fisker Ocean Ultra - deposit paid.

Just leave it on permanently 🤔 Landrover - turning owners into mechanics since 1948

2014 Orkney grey Freelander SD4 GS.
2004 Zambezi silver Discovery 2 Td5 (Gone)
1963 Surf blue Morris Mini Minor Super de Luxe (my little toy)

i leave mine on permanently,but use it quite a lot.