Sorry but you only have yourself to blame a written contract signed by both parties is the first thing should be undertaken before any work commences. There are various way to do this written or electronically. Judge Rinder says it often enough text messages/emails ect all count.
A lot do it to remove all the dirt prior to milling saves the blades getting blunt. I mill using a bandsaw mill and jet wash dirty logs covered in soil. Hot weather as well as others mentioned stops drying to quick.
6X6 metre workshop is for hobby users and simple not big enough to run a business from. I have an 8x5m and there is simply no room to assemble anything and fit my machines in there.