@Karl_M
I'd be taking it back now too mate. Make sure you tell them that the steering wheel needs to be centred and the front wheels aligned (adjusting toe in/toe out) so they both point straight ahead, relative to the steering wheel position. Tell them to take the steering wheel off if needed and/or perform the steering alignment - whatever combo is needed to get it all straight!
Otherwise, they'll just align all 4 wheels so your car travels straight, but your steering wheel will still be off centre. (like they did to me

)
Seems these days with some mechanics (especially mobile phone companys, utility companys, banks and their bills), you have to explain things in depth while still keeping it in baby talk so they 'get it'. Then sometimes you have to make sure that they did their job properly like some sort of school teacher or ticket inspector!
I really hate being like that and don't want to be a pest or be 'one of those customers' but sometimes you have to follow them closer than normal to get things done properly.