Audi tt gear selection problem. please help

Hi, not sure if this post is on the right section but i need some help.
I have a 2001 TT roadster 225 6 speed manual with a few problems. Sometimes it is really difficult to get it to go into ANY gear but once you do and the car moves I am able to find the rest of the gears.

I have reset the gear linkageVW Group shift linkage adjustment on Vimeo and initially thought it was better. Drove round the block and gear changes were a little notchy but went into all gears and pulled okay but after reversing onto the drive checked it again and it was impossible to get it to go into any gear with the engine running.
With the engine off it was back to normal (a bit notchy but all gears engaging) so i tried again with the engine running and it refused to go into gear. With the engine off i put it into gear pressed on the clutch and started the engine then cycled all gears which seems to work.

You can push the selector on top of the gearbox to engage all gears, it does this quite smoothly but once a gear is selected there seems too much up/down play in the gear selector shaft.
I am wondering if the rivet that holds the selector fork engager might have come loose, but for it to happen in every gear surely all rivets would have to be loose?

Why is it only hard to find gears with the engine running but after starting the car in gear it is okay?

Also have no power to convertible roof, remote central locking, boot and fuel cap release but i have found the climate control module behind the drivers seat and this shows signs of water ingress so will be replacing that after sorting the gearbox, my only concern with this is that the dashboard light for the roof deos nothing even when the car is 1st turned on, if the comfort control mudule is ******* would this kill all power concerning the roof, even the dash light?

Update! It was the flywheel. I asked a specialist who said if there is too much play in the flywheel it will " get a wobble on" preventing smooth gear changes. I replaced the clutch and flywheel myself (it can be done with one man, as long as that man owns a lot of axle stands) And the problem was no more.
The roof was fixed by changing the roof control module, the drain traps on the rear parcel shelf were blocked causing rainwater to flow onto the module and fried it.

The TT is now sold and I have an A4 cab 1.8T with water ingress problems. I think these germans are selling us cars using the reliable reputation of yester-year.