Employer notified resignation after 7 months:cooling-off

I was issued Tier 2 General visa valid from 01.10.2013 to 31.10.2016. I resigned from work for this employer on 21.02.2014 and left UK on 26.02.2014. While serving notice period I had informed the HR to notify to the UKBA regarding my resignation. I recently checked with this HR, but the HR has informed me that they did not notify the Home Office about my resignation until I checked with them on 02.10.204 subsequently they notified through the SMS online portal. I have a new COS but learnt that I cannot make new application under Tier2 by applying outside of the UK until my cooling-off period completes.
I would like to know due to this delayed notification, does it have an effect on my 'cooling-off period' start date! I have my last pay slip, P45, flight ticket, boarding pass of leaving UK and not returned to UK by any other visa! The Tier 2 guidance policy states in point 26, I can show evidence of leaving UK, provided the employer entered my last date of employment via SMS report online!
The notification has been made only after 7 plus months and it's not my fault and the HR has failed to comply with the sponsor rules. Hence, my enquiry is to clarify when my 'cooling-off period' starts and ends, i.e., 26.02.2014 (the day I left UK?).
Kindly provide advise on this issue and if there is an option I should get a detailed clarification it would be really helpful!

Starts on the day you left the UK. I left in Feb and went for a visit in July and I was told my employer hadn't informed them for a while. It's all good if you can prove you have not been in the UK on a Tier 2 since you left.

Hi swgirl,
Thanks for the info! The passport should show entry stamp of returning date to my Country, so that should suffice, providing with my last pay slip, P 45, flight ticket and boarding pass as well! These are the only evidence that can be provided of leaving and not been in the UK!