Need some help with gear adjustment , my 1st gear is now reverse

My car (Octavia vRS 2007) has just been written off and I was removing my forge short shifter. I installed it myself with no issues and have done the exact same process to put the OEM back in but I cannot get it setup correctly. I released both adjusters, Locked the gear stick in place and pushed in the transmission lock pin then released the tension to lock the cables to the shifter. I've tried multiple different ways but It won't work and It mainly seems to end up not being able to engage 2nd gear. Even with the cables disconnected from the shifter on the gearbox I can't seem to push the shifter into what should be the 2nd gear position. They are going to collect it to inspect and I'm worried this will affect the value as It wasn't related to the accident. If anyone has any ideas it would be much appreciated. Thanks :)