Tier 2 (General) Change of employer of visa application

[AVC]

Hi All,

I am in the process of changing my employer on Tier 2 (general) visa. I am planning to apply through the premium service appointment (as it will be quicker) once I'm provided with the COS from the new employer. I had few queries regarding this process:
1. What are important things to check in the COS before applying for the visa?
2.I had specific question related to start date on COS, if its not possible to start on the stated start date on COS due to that fact if I am serving notice with the old employer? Will it be ok if I'm still working with the old employer after the stated start date on COS?
3. What are the documents which need to be provided when going for premium service appointment?
4. Do I need to need pay the Health surcharge again with this application as I already paid once with my (general) application this year?


Thanks

[CR001]

I will answer the one that I can.

4. Yes, you must pay IHS with each application you make.