Thank you MW

Although the will of my late mother was signed and witnessed it doesn't contain a proper attestation clause. Therefore 5 months after placing this for a solicitor to deal with they have come back telling me that the Probate Registry needs an additional affidavit swearing that the witnesses signed in the presence of my mother when she signed the will. Where do I find the form or is it better that I pay for the solicitor to draw up a form? Am loathe to spend out more money as I think he should have told me of the problem 5 months ago. Thanks in advance]