in written busin.

[Dok]

Можно ли использовать в официальных документах клише in written в контексте:
Thank you in advance for your cooperation and kind attitude. We look forward to receiving your response in written to the address first above written in the course of three business days since the date hereof.
В отдельности и без употребления существительного FORM ( in written form)

[rustik@safecap]

in writing

[october]

Док, пишем in writing

[Slava]

Вместо kind attitude я бы написал interest (возм. еще варианты).
in the course of - within.
since - from