Google docs spread sheet to be re-edited / restored

We have a Google Docs spreadsheet that a number of us edit and re-edit as months go by. I have just discovered that on April 22 2018 a large corruption took place which manifests as 77 edits on a single day. It is easy to go back to the date before this accident April 18 2018 and restore that document. But there have been approximately 30 days since this date when someone has "correctly" added in new information (usualy 1 - 10 edits per day) to update the spreadsheet.

I need someone who understands google docs spreadsheets well to carefully,

a) restore the spreadsheet to the pre-corrupted version April 18 2018
b) copy and paste each of the correct edits from mid May onwards into the restored version of the file.
c) save the document as the up to date file ready for further work.

The work needs someone very familiar with google docs spreadsheets and who has care and patience.

A will put a nominal figure in teh budget cell but really am asking for quotes.

The google doc can be viewed here https://docs.google.com/spreadsheets/d/1E7eXBf1NF1oWpCYdQ5BlcAVF_DlfR0sjPjYnw9WTXB0/edit?ts=5787da66#gid=0