Okay so i have nitromorsed it but around the corners is still some remnants of paint, i have already been through one dremel bit. Does this need removing or will it be okay?

Are they blasting it? That'll take off any minor debri if done properly. In anycase when it comes to painting steel, the preparation of the surface is everything.

Best thing would be to let the folks that are going to powder coat it, give it a sand blast, thats what my painter did with my frame and made a great job.

na the powder coaters don't do bead blasting otherwise I would have. So what your saying is put in the elbow grease? 👿

If there's remnants of paint then get some more Nitrimors on it till it does come off. It will either bubble up under the powder or the powder wont stick to the painted bit. (its put on electrostatically).
Give it a good wash in hot soapy water then let it dry somewhere warm for a few days, making sure the water drains away. If you can get it lightly blasted it will look loads better.

My powder coaters don't beed blast as it takes them ages and hassle to swap it from one type of blast to the other.

However I have had lots of frames blasted and never had a problem, just make sure they don't spend ages on it and don't work on one spot for too long.

Most bike paint comes off pretty easy. I took a frame in once and he said I'll just see how tough the paint is, popped it in the blaster, 30 secs later he took it out with me expecting to see a small area done but 80% had already come off!!