Mandate your wife must absolutely seek legal advice. Whilst the other posters say there is no negligence, this is fact sensitive. I cannot say she has a good case, but it is not as woeful as the other posters make out. If you can read White v Jones, that gives an overview of the law in this area, there are further cases on point. Please seek the advice of an appropriately qualified lawyer.
To those who say there is no negligence, with respect, unless you have considered the full tests of negligence together with the facts, it is impossible to say. I can't say, but what I can say is that the OP needs further specialist advice.
As to your final question OP, yes, the solicitor does owe a duty to the beneficiary. This was first suggested in Ross and Caunters and confirmed by the HoL in White v Jones.