Who would I contact to buy these products. I’ve only had the car 2 weeksI bet it's the shifter ball in the shifter housing.
Disconnect the linkage and check that it's not actually the gearbox selector been stiff, which I highly doubt, but worth checking.
Maybe time to upgrade to a taboo stiff shift or a PM's shifter?
If running a standard plastic ball there's no reason for it to seize up. On the BMS and other similar shifters the standard ball is stiffened up and it still centres fine.That spring won't cause the lever to go stiff, I removed it on my last 172 as it broke, all it did was make the shifter not spring back to central as quickly in neutral.
The ops video looks clearly seized to me