I was able to solve the issue using following lines of code -

Using apostrophe!

Please note - I still use Robot Framework SSH Library.

All this code is running from a .robot file and executes on a remote machine with a SSH connection open!

    ${part1} =   Set Variable    py ""${remote_file_full_path}
    ${part2} =   Set Variable     --id 11064 --output C:\\Sandeep\\process_output.txt""
    ${part3} =   Catenate    ${part1}    ${part2}

      ${status}=  Execute Command  ${part3}  return_stderr=True  return_stdout=True  

thanks!