when to enter uk after tier 2 visa is granted?

[ironica]

Hi, i would like to ask if theres a time limit or up to when to enter uk once tier 2 general visa is granted.

my visa was granted August 13,2019 but the start of my work will be by September 27, 2019, COS will expire by October 2, 2019. i heard from someone that i should be in uk within 28 days after my visa is granted is it true? if it is wont it be a problem for me to come to uk 2 weeks prior my start date? like,i can come to the UK 2 weeks before my start date without a problem? would i need to provide some documents to justify why i came early before my work date starts? what documents would those be? im really worried so i hope you guys could answer my questions.
thank you for the assistance. all info given will help alot.

Kind regards ^_^

[CR001]

Your initial visa is valid for 30 days. You must enter the UK within that time.

[SKJ1984]

Check in your vignette visa page and see the expiry date in it. It will be usually 30 days. You must come into UK and collect your BRP within this expiry date.
You are not supposed to work before your CoS start date.
You can come earlier than the CoS start date and find a house, get familier with new place, that is the time given to settle in a new place.

You are entitled to enter UK with a valid visa and it is you and your employers responsibility not to start work before COS date.

Have your offer letter , TB clearance (if applicable) , BRP collection letter and the address of your stay in UK handy Border control does not ask anything beyond this. ( ofcourse passport )