I looked at the description of the covenant that Pralix posted and figured we will want to discuss some details.
First, did a quick search about the area and there is a village called Lavoûte-Chilhac is quite close to Chilhac to the west -- about 2-3 km distant. Wikipedia indicates that these is a priory there, called Sainte-Croix de Lavoûte-Chilhac. The priory's construction was completed in 1040 and it owned about 300 hectares of land, so it would be a significant entity in the region. Does it exist in the saga?
From the size of the village (population 89), establishing a covenant may have a significant impact on the locals. If we have 5 magi, that probably means 20-30 mundanes to support them. How will we feed them? How will we establish sources of income without interfering too much with mundanes? We need to start thinking about that. A few possibilities come to mind, such as mining, sheep-related industries (spinning or parchment-making), or farming (probably after clearing unused land). Most of these require some sort of rights to be granted to us from the nobility. These sources of income need not be located at the covenant site itself.
Now, there is the site of the covenant and the aura. How large is it? If it is centered on a ring of stones, that may limit how much buildings we can set up. Unless there are caves? We may have to build downward into the ground, particularly if we want to stay unconspicuous. The privacy of the site will need to be taken into account, since we will only be 1 km from the village and local shepherds probably move their flocks nearby. Unless there are legends related to the stones that keep the locals away?