IELTS is not require according to SINP website for reference you can visit the SINP immigration website and check the general question.
SINP web site clealy mention in general questions that you can prove your english language requirement from one of the following.
How can I meet the language requirements?
If you were educated in a country where the first language is English you may not need additional proof of your language ability. If your first language is not English you must prove your English language ability with one of the following:
SINP 500-8 Affidavit of English Language Ability
If you have a job offer from a Saskatchewan employer, they must complete this form to verify that you have language skills necessary to do the job;
Education/training documents that demonstrate you have attended education institutions where the language of instruction was English/French and show the length of the program;
Language testing results that equal a score of six or greater on the International English Language Testing System (IELTS);
Certificates of English/French Language training with a letter that shows the length of the program; or
Employment references with English/French as the principal language of communication.
So if any one who is receiving the letter from the CIC office in London or any other visa office asking about IELTS they can contact to the SINP Manager Mr.David Li or Tracy and mention them the above link of requirement of SINP according to their website or application guide. we should contact to SINP office to Solve this Issue. Thanks and good luck with immigration Process.