Hello and thanks for using Just Answer.
My name is ***** ***** am happy to assist you with your enquiry.
Having looked into matters, I do confirm that Star Legal took over Burke & Co, and as such any Deeds and Wills/Powers of Attorney should still safely be stored by Star Legal.
I am not sure if they are denying responsibility for your Wills/Powers of Attorney, but upon them acquiring Burke & Co, they should have written to all clients for whom they were holding Deeds/documents, and retained them safely.
You should therefore go back to Star Legal (ideally,with evidence you may have that Burke & Co were holding your documents) and ask them to search further for them.
If it turns out that they have mislaid them, they should offer to prepare new documents for you, free of charge, if this is feasible.
You may also want to contact the Solicitors Regulation Authority (SRA), who deal with Solciitors complaints, and lodge a complaint with them. Their phone number is 0370(###) ###-####
(They will ask you to try and resolve matters directly with Star Legal, before they are likely to get involved).
I hope this assists and sets out the legal position.
I will leave your question open and will await hearing from you tomorrow.