Opel Astra-H, first gear won't engage

I have an Astra-H with an M32 gearbox, and the first gear isn't engaging properly. You can push the gear lever into the first gear position, but it always ends up in third gear.

The part at the top of the gear lever where the cables are attached is loose, and I suspect that's the problem.
Is there perhaps an Opel mechanic here who can tell me if it's possible to remove the gear stick without having to remove and disassemble the transmission? I'm worried that the shift forks/shaft/gears might get twisted, and then I won't be able to reassemble everything.

Do you know this?

http://wiki.corsa-d.de/wiki/images/Feldabhilfe_2305_Getriebe_M20_M32_Fehlfunktion.pdf

Thank you.

I wasn't aware of that issue. In my car, all the gears shift normally and easily, but instead of engaging first gear, it always goes into third. And because the shift linkage has so much play, I hope it's only due to that and not because of a bent shift fork.