Chatbots are increasingly being applied in the context of healthcare, providing access to services when there are constraints on human resources. Simple, rule-based chatbots are suited to high-volume, repetitive tasks and can therefore be used effectively in providing users with important health information. In this viewpoint paper, we report on the implementation of a chatbot service called Ask Anxia® as part of a wider provision of information and support services offered by the UK national charity, Anxiety UK. We reflect on the changes made to the chatbot over the course of approximately 18 months as the Anxiety UK team monitored its performance and responded to recurrent themes in user queries by developing further information and services. We demonstrate how corpus linguistics can contribute to the evaluation of user queries and the optimisation of responses. Based on these observations of how Anxiety UK has developed its own chatbot service, we offer recommendations for organisations looking to add automated conversational interfaces to their services.