House for sale advertised as Section 27 tax designation

I have come across a houze built circa 1940 for sale privately and it's advertised as a section 27 tax designation.

The vendor doesn't know what it means and I assume it was such a property when she purchased it over 20 years ago.

Can anyone throw any light on this and would it have any implications today on me buying it ?

Ask the vendor's solicitor to provide the documentation that supports their assertion of "Section 27 tax designation" and see what that says.

See Owner Occupier Relief, and Section 27 of the 1987 Finance Act (modified since)