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i can help you for your concerns.
she can give you this notice in the presence of witness. . she can send you email and can have prove for this.
she can send a first class post and can have a proof of sending.
you have explained that if she sends recorded delivery but you do not accept then the sending proof will be enough for her to prove that the she tried to serve the notice but you did not accept.
i hope it will help you
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