Thank you for your query.
Essentially your question is whether you can use the scanned copy as evidence of consent from your Sponsor.
The answer to your question is set out in the Tier 2 Policy Guidance which can be found here:
The relevant section applicable to you states:
You may have been sponsored in your studies by Her Majesty’s Government, your home government or any international scholarship agency. For the purpose of this section of the guidance ’sponsored’ means wholly supported by an award which covers both fees and living costs. If you have had such sponsorship within the past 12 months, you must provide us with the Government or international scholarship agency’s unconditional consent in writing, giving you their permission to remain in or re-enter the UK.
18. Any documentary evidence that you provide must be issued by an authorised official of the issuing organisation and be:
original (unless we say otherwise); and
on the official letter-headed paper or stationery of the organisation.
It is clear from the above guidance that is compulsory to provide the original letter. You could ask your employer to contact the Home Office as see if they will accept the scanned copy. The above guidance (see italic and underlined) that the may be able to accept scanned copy if they agree.
Otherwise, it is simply up to the discretion of the Home Office if they will accept the scanned copy or not.
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