I've only just started making a concerted effort to locate the breeding signs and non-adult stages of lepidoptera in my garden, so it is encouraging to come across a significant find like this so soon.
This is a very locally distributed species with a stronghold in parts of East Anglia and is designated "Notable B". A recent study has found it in suitable habitat in several parts of East Anglia including the Peterborough area.
These two were feeding on Primula, although it has been recorded feeding on other low plants as well as this. The next challenge is to record the adult. They are scarce at light and come more readily to sugar or flowers.
Square-spotted Clay (Xestia rhomboidea)