Tier-2 Change of Employment Notice period

Hi,
I have been granted change of employment Tier-2 visa, details are as follows;
New Tier-2 visa issue date - 15th October 2018
CoS start date - 25th October 2018.

My notice period with my current employer is 4 weeks. I have put my notice on 17th October 2018 and plan to continue working for existing employer until 16th November.

Start date on my formal offer with new employer is 19th November 2018 (which is within 28 days of CoS start date). Can somebody please advise if I can continue to work for my current employer until 16th November which is within the 28 days of the start date of the new visa?