The neck has been sitting for a bit over a week curing so I gave it an oil. On close inspection the rosewood has a couple of issues. I will change the nut anyway so I hope a light sand will sort the scratches out there. The crack in the fretboard at the other end I am not sure about. Is there anything I should do to stop it getting worse? Honestly I will never get there the way I play but it is a good lesson to have a really good look at the kit when it arrives (or any guitar bits). I did a practice fret level, crown and polish on an old beat up neck I had. It was a great learning experience and gives me more confidence going forwards with this neck (and others I have from 2nd hand guitars that need work).
I used a cheap fret crowning file. I think in the future I would get a better quality one or use some of the wood and sandpaper designs I have seen online. Also getting a fingernail buffing block was a great. It worked really well at the end stages to polish the frets.
I am really enjoying the learning experience.
Nearly ready to start the next build for one of my boys. Lime green dye ash strat with black hardware. Will post a link when I get it going. Again thanks the the community for the great advice and support.