Hope you get it mate.
Car allowance would be sweet, then you can keep the Mazda for fine days and the GTI for the track. Oh and get a diesel company car that could tow the Golf on a trailer

I've also got an interview tomorrow. Like you it's internal for a more senior role, more responsibility, more paperwork, but better hours and more pay. The only thing is it's not permanent, it's 9 months covering for someone who's working on a project. Though it would be good experience and could lead to a permanent job and if not, I just go back to my old one.
Good luck to you Nick.