Here is a discussion about whether to use ご返事 and お返事, but there seems to be diverging opinions:
- ご返事 is 謙譲語 (according to No.1)
- ご返事 is seldom used for 尊敬語 (according to No.5)
- ご返事 is for 謙譲語 AND 尊敬語 (according to No.4)
- お返事 implies intimacy (according to No.1)
- お返事 is 美化語 (according to No.4)
Given that I always write in the context of business (sometimes about my reply, sometimes about my client's reply), can I stick to always using ご返事 ?