Enter UK before COS start date

[bks]

My employer will submit my cos application this july. My COS start date would be on October 5.
Once I have my visa, can I enter the UK a month before my cos start date ? I’m planning to spend some quality time with my parents(both are living in the UK) before I start my work.

[thisB]

You can enter 14 days before the start date on your certificate. https://www.gov.uk/tier-2-general

I would assume that if you enter before then, you could enter on a tourist visit and leave the country to reenter on Tier 2, but keep in mind it would depend if the border thought you were a legitimate visitor.