There's no need for the executor(s) to use a solicitor but they might choose to do so if the information obtained from the links below leaves them confused!
As others have said, any expenditure involved in transferring the title to the property should be met from the testator's estate.
See this link for the relevant document from the Land Registry:
http://www1.landregis.../public_guide_009.pdf
To download any of the forms referred to there, start here:
http://www.landregistry.gov.uk/
Click on 'Forms/Publications', at the top left, and then on 'Forms'.
Chris