Everything that is in the standard form Find A Tender Service (FTS) notice – all fields are mandatory save where not applicable. If a contracting authority is publishing an FTS notice on a merely voluntary basis (where the 2015 Regulations do not apply) it is common to include a statement in the notice that, while the contracting authority has decided to advertise on a voluntary basis, does not represent a commitment to follow one of the official procurement procedures. However, even where this statement is included, we would recommend that in practice the contracting authority aims to follow one of the official contract award procedures.
Note that Regulation 53 requires the "procurement documents" to be made available electronically from the date of the advertisement, which should include now the internet link where the procurement documents are accessible.