Here is the confirmation email from Guinness book .
Dear Mr Gurmej Singh,
We are delighted to confirm that you have successfully achieved a new GUINNESS WORLD RECORDS title for ’Longest painting by an individual’. We would like to congratulate you on your record-breaking achievement. You are OFFICIALLY AMAZING.
Your official GUINNESS WORLD RECORDS certificate confirming your world record is being created and will be sent to you within ten working days.
This is non official certificate from the Guinness website and original is coming via mail.