Bugle

Autumn or early spring (lateFeb/Mar) really, less chance of it dying from drought

Now is a good time. It should be sending out runners like a strawberry plant does. These root as they touch the soil so you can dig them up and move them to a new site. Keep them watered over summer.

i divide mine after it has flowered but usually it sends out runners that i treat like strawberries.

if you plant the runners in individual pot while they are still attached to the parent plant, they will grow roots and then you can separate them.