I've got a few scratches on my Anthracite Grey car, I've tried scratch X and even grey t-cut but they aren't going so the next idea is small amount of paint.

I've been halfords and they didnt do the colour, but checking online they do Anthracite Grey for a VW which I'm guessing is the same colour? And obviously skids do one. But what's the best/easiest for application? They aren't deep and are only about a mm thick so a tooth pick would probably be best to apply it?

I doubt you would get a decent finish doing it that way - especially with that lovely colour (I have the same colour on my pride and joy). Why not consider going to a professional who cold either touch up the paint or use a professional polishing compound. I have used things like chips away or similar before with brill results.

can you feel scratches with a fingernail when you go over them? If not, wet sanding might work - i.e cutting back the scratched lacquer to the good lacquer under the scratch and then polish back up. Not an easy task though.

As per Devonutopia. I posted last weekend that I have just scratched my car with a jet wash pipe. Fine sanding and mop will take out fairly deep scratches. The whole job, roof, wing, boot, bonnet with resprayed rear spoiler quoted £150. I decided to have some more panels painted. If it's just a few scratches you could probably get it done for £50-100.