Aux drivebelt tensioner on sharan mk1 with aircon

[dazar5]

Hello

I need to change my aux drivebelt and it is the double belt mk1 with aircon sharan model. My problem is that the only way I can see to release the tension to remove the belt is to adjust the cogged bolt that join to the power steering pump. This bolt looks fairly corroded and has a damaged tooth. Before I try this I wanted to find out if
1: This is the only way to remove and replace the belt
2: Is the bolt replaceable or is it part of the power steering pump assembly (which is bit to expensive to replace right now)