Impact of delay in start of employment on Visa validity

[siddzy]

Hi. I have a doubt with regards to my visa stampings' validity in case of delay in starting my travel.
Category: Tier-2(General)
Details: My CoS has an expiry date (to be used by) 17th August2012
It also states start date as 28-May-2012 and end date as 27-May-2012
My Visa has been stamped for three years with an expiry date of 27-May-2015.
However there has been a delay on start of my employment in UK and I am unable to travel before August 17th.
Q-Will that mean that I have to apply for fresh stamping/CoS?
Can I still travel on visa after 17th August?

[manci]

The 17 August CoS expiry date is no longer relevant since you have been issued with a visa and the CoS is now "used".

You can travel to the UK any time within the validity of your visa but a new work start date must be agreed with your employer since it will presumably be different from what has been stated in your CoS.