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Ok, so the answer is Yes you can because it would seem that you have only just left the UK. The requirement is that Skilled Worker visa holders applying for ILR must not have spent more than 180 days outside the UK in any 12 month period throughout the five year qualifying period. This is due to the requirement to show "continued residence" in the UK prior to making the application.
does this clarify your question today?
Ah ok, yes I completely understand your concern. Yes, in light of the fact your Tier4 visa expired and you are no longer in the UK this would be inaccurate to apply for a skill worker visa using this COS. I would strongly recommend that you speak with your employer to request a new COS which correctly states your new circumstances IE you will be making a fresh application for skilled worker visa
I hope this makes sense? In the circumstances I do not recommend using your current COS until you have a new one.
No problem happy to help. Please do not hesitate to contact me if you require any further help and assistance. Daniel