Interview help!

[Mylifesarainbow]

Qualified primary teacher on maternity leave. I've decided not to go back to teaching for various reasons but still love the teaching aspect and working with children.
Have applied for a job as HLTA with phonics specialism and have an interview next Wednesday.
Need some advice - firstly, any ideas of types of interview questions I might be asked would be helpful. Similar to teaching interviews I imagine but anything specific to a HLTA role?
Secondly, the school uses letters and sounds which I'm a bit meh about and - if successful as phonics lead - I would hope to implement RWI across the school. SO do I teach a letters and sounds based lesson that's a bit wishy washy but fits with their current system? Or so I do a RWI lesson which I am extremely confident with and know I will execute well and then discuss this during the interview stage? They have only stipulated teaching phase 4 'gr' so I can do this using RWI method.
I'm very confused and need some advise from people who know what I'm talking about. No friends or family in RL work in schools and so just look blankly when I start waffling about graphemes and blending!