Technically copy-editing is roughly £23-25 per hour. Proofreading - where less is needed, is £20 per hour. They are tricky skills. Well done for getting it edited - there is so much available on Kindle that is shockingly flung together. I am sure that a professional presentation would make all the difference.
I'm an editor - I've worked for the major publishers for 20 years. Not sure how you find someone reputable on a freelance basis. People per hour might come up w someone but not sure how good they are really.