Hello Richard
I would think it will be the standard competency based interview and as HST will be based on Customer Service maybe with a 'tell me about a time you were in an emergency situation'. The customer ones are likely to be 'tell me about a time you recieved/gave great customer service' or 'tell me about a time you had to deal with a difficult customer'. try to answer these in the STAR format Situation, Task, ACtion, Results. Always describe YOUR role and not WE. Use real situations NOT hypothetical ones e.g NOT if this happened I would do that, or if I had a difficult customer I would listen to them carefully and then talk calmly to them, you must talk about something YOU did. Don't lie or you will get caught out. when answering describe the Situation in 10% of the answer e.g I was working on a customer service desk, then Task 15-20% I had to deal with all customer complaints in a sensitive manner, 50% saying what happened and how YOU dealt with it, NO we or the team. Then use the rest of the answer to describe the POSITIVE result.
Have a few examples written down, and good luck.