The one who runs your script offshore must have configured verbose logging in WinSCP GUI:
https://winscp.net/eng/docs/ui_pref_logging

The script by default uses settings from GUI.
Unless you isolate the script configuration, what is recommended:
https://winscp.net/eng/docs/scripting#configuration

I have batch script that SFTPs from Windows 7 to Linux 2.6.18-422.el5 #1 SMP x86_64 GNU/Linux.

When I execute the batch script (from USA) that invokes Winscp, I find no issues and the data file is transferred to Linux within 2 minutes and the log file is neat without any hexa values.

If someone from offshore (Canada/India) executes the same script, it takes about 8 minutes and writes gibberish hexa values to the log file. The lines in log file with Hexa values are almost equal to the number of lines in data file.

Please see part of the log below. The Hexa numbers continues after "Type:SSH_FXP_WRITE.."

. 2017-11-01 15:07:41.991 Write request offset: 25795180, len: 32735
> 2017-11-01 15:07:41.992 Type: SSH_FXP_WRITE, Size: 32764, Number: 1286
> 2017-11-01 15:07:42.002 06,00,00,05,06,00,00,00,08,06,D4,AC,10,06,D4,AE,50,00,00,00,00,01,89,9A,6C,
> 2017-11-01 15:07:42.003 00,00,7F,DF,33,2E,35,35,33,2C,45,4E,54,45,52,20,41,73,6B,2C,2C,33,39,2C,2C,

Appreciate your help, how to stop only the Hexa value part from the log.
Also let me know what to do to speed up the script when executed in offshore.

The WinSCP is installed through SSH Tools. It is installed along with PuTTY.