Finetune manuscripts in English

We are a Belgian publishing house that works with Dutchspeaking and writing authors. We are looking for someone to help us tweak and finetune our manuscripts. In order to get started, we are running our manuscripts through DeepL, but of course this isn’t perfect English. We are currently searching for a corrector who can help us finetine these manuscripts.
The first one is a Young Adult of 85.000 words that needs tweaking. Deadline is one month from today. It is simple language to correct, but the work will focus mostly also on grammar and spellchecks, and setting the sentences right (in British English). So we are looking for a native English speaker.

The budget is an indication.
In attach a sample.

Let me know if you have any questions.

Thanks