COS wrong category after applying healthcare work visa

[Mohamed88]

So I am on graduate visa working with my employer for 7 months now (graduate end date 25/06/2025). I believe my HR did a mistake with the COS.

She did the category as Graduate in tier 4/ student route switching to skilled worker. Now I have just submitted my application (25th December) but luckily couldn't book an appointment because the page kept stuck on loading.

I now realised the COS mistake, but HR isn't back till 9th January.

I have a few questions ( Obviously will discuss with HR before doing anything)

1) should I cancel my UKVI application through the online form and make my employer request a new COS ( hopefully that mean I get a refund with no change to my current leave)

OR

go ahead and book appointment (when the loading issue get fixed), expect HR to receive an email to pay the immigration surcharge from the home office like I found othe results on Reddit.

2) I believe start and end dates can be amended on the current COS. Start date is 18 December 2023/ end date is 17 December 2028. Would it be possible if I amend it a month in advance so I can get a full 5 years on the work visa to easily secure ILR after that. Or what start date would be the best so I don't need to reapply.

Many thanks in advance for your help.