Hi Gaetano
The stanchion bases for the 36 Classic were made by Goiot in France but I think they are no longer making them. They do still make the stanchion gates or you can get identical ones from Plastimo for less than half the price. When I added gates to our 36C in 2020 the bases were still available but very expensive at about 90 euros each.
It may be worth contacting Goiot to see if they still have some of the bases in stock.
Good luck
Andrew