Form RF134:
https://www.motortax.ie/OMT/pdf/RF134_en.pdf
i had to use this before to get a lost tax book before
had to be signed bye a guard
your problem is that the previous owner is the one who has to sign it
this must be why you have to get it signed bye a solicitor
just googled there and found info below
1. RF134
Standard lost documents form. Completed at your local Garda Station, signed there.
2. Declaration
Signed by Peace Commissioner / Commissioner of Oaths / Solicitor [Must be stamped]
Signed by local main dealer for the car in question, dated, to say that they've inspected the VIN and it is genuine.
After that it's €12 and into an envelope to Shannon.
DECLARATION AND AFFIDAVIT ARE THE SAME THINK I ASSUME SO FOLLOW INSTRUCTIONS BELOW
Affidavit forms can be obtained at any of the Motor Taxation Area offices and should be signed in the presence of a Commissioner of Oaths/Practicing Solicitor.
Change of ownership - Person purchases vehicle, previous owner has lost VLC/VRC or person cannot locate previous owner.
For vehicles registered after 01/01/1993
New owner get affidavit completed & sends the form to Shannon directly themselves or take the completed affidavit into the Motor Tax Office who will forward the form to Shannon (there is no necessity for an RF134 form to be completed nor is there a fee involved). Shannon will then update the Computer System with the new owners details and a new Vehicle Registration Certificate will issue to the new owner.
http://www.donegalcoco.ie/services/informationpoints/roadusers/changevehicleownership.htm
http://www.boards.ie/vbulletin/showthread.php?t=2056321375
http://www.environ.ie/en/Publications/LocalGovernment/MotorTax/
HOPE THIS HELPS 