Tailgate issue

[Mr. P]

The last few days I've noticed an intermittent problem with opening the tailgate (2004 AWX 130 PD Highline).

I can unlock it as normal with no problems at all - either by pressing the button on the key or pressing the switch on the drivers door.

However when I go to lift open the tailgate, the switch/lever/handle (not sure what it's called) that is covered in a rubber like substance, that you press as you lift the tailgate doesn't seem to click as I depress it so I can't actually open it. Although it does eventually free up enough so I can open it. It's as though the bits inside have stuck and not released freely? Not every time though. I'm assuming this part is just worn and needs replacing? Or is there something I could do to free it up, i.e. does it just need removing, cleaning and re-lubricating?

The car has done over 250k miles so it has had plenty of use...

I reckon I need to deal with this sooner rather than later before it packs up completely....

Is it a simple job to do, etc etc?

TIA
Pat.