The aspect ratio issue is still present @mittadj. You should be able to get a good quality cut from this no problem, but please crop the source before using remove.bg and maintain aspect ratio and constrain proportions when cropping, otherwise I'll keep rejecting your cuts for the same reasons.

I think the problem was with the first cut that i've used a much smaller source for the cut. I hope that my second cut is now more acceptable! 

The bigger and better the source image, the bigger and better will the eventual cut be. It's worth spending time looking for the best possible source rather than cutting the first one which comes to hand. Here's a thread with some hints on how to locate the best source images.

It's still not sharp enough given the source available, however. This is what I've produced - as you can see, it is that little bit sharper. Can I ask what program/technique you're using?

I use Photopea and Remove.bg. Before I put the image true Remove.bg, I crop the head, neck and a bit of collar out of the image. After removing the background I crop the image in Photopea later on at the right dimension you asked for the cuts, if it is necessary. But something in the crop process I do wrong, I think.

Hmm, that seems to be the correct way to go about it. Can't think what might be the cause of it 😢