Stupid question of the day: Can I 'water' an olive plant with olive oil?

[selfraising]

Nickerly, for what its worth I don't think you've over re-acted. If the bottle is not clearly labelled that it may contain nuts, I think it should be investigated. Fortunately your husband had a mild re-action but there are lots of people who could go into anaphylaxis, so I think it's quite responsible of you to notify trading standards.