Clutch bellows when cold

Hi guys, I would like to have an opinione on what happens to my Def. First of all it's a Defender 90 Td5 MY06 with 150.000km
The problem is that in winter when the car is cold, when I press the clutch pedal I hear a WUUUUUUUUUUUUUUUUUUUUUUU that lasts as long as the clutch is pressed. This noise appears always, with the transmission in neutral , selecting short and long range.

During that noise is impossible to insert or remove any gear: if I try to insert a gear the sound increases and when the problem appears with a gear inside the car goes on as the cluch wasn't free.

To go on i try to put one random gear and after I can put 1st and go. In the worst cases there was no way to insert any gear so I had to turn off the car, put the gear and then turn the car on.

Once started, however, before I can make a few kilometers I have to make a couple of crosses in short distance: when I stop and I press the clutch bellows and the car continues to move forward so I have to brake and force a little to remove the gear.

Once the car is hot i don't have any kind of problem, gearbox and clutch work perfectly.

I have MTF94 fresh oil in gearbox and clutch fluid is correct, fresh and purged.

I heard that the problem is a ****ing bush (Spigot Bush 8566L LBF500050) and to fix it, in practice, you change the clutch in the meantime ... but, I mean, it seems to me something serious...

Am I the only one? What would you do?

Thanks

could be the spigot bush ,normally spigot bush is only noisy when clutch not fully released ie noisy when pedal half pressed, which your symptoms could give as clutch obviously isnt fully released as you cant select gears ,why you cant release clutch could be air in the system or very tight bush ,youd have to prove clutch hydraulics are good to leave you with bush as fault