We have caught (and killed I am afraid to say) our first mole. It's not a nice feeling but they started it. And information (below) suggests why we got targeted (following the floods) and that there maybe more moles around.
We can only wait and see.
Moles are solitary but not as solitary as people think. Sharing the main runs under hedges and fences, but will defend their own territories aggressively. Territories will overlap and this is why when a mole is caught or vacates its territory another mole will sense this that it has been vacated and will quickly move into the vacated territory.
The moles have several layers of tunnels, shallow short lived surface tunnels, and deeper tunnels used for breeding and feeding. The large mole FORTRESS the very large molehill one frequently sees, are usually found in areas of high water tables or on land which can become flooded.