An industrial vehicle comprising industrial vehicle hardware, a tag reader, a reader module, a user interface, and a vehicle controller wherein: the industrial vehicle hardware comprises storage and retrieval hardware and a vehicle drive mechanism; the tag reader and the reader module cooperate to identify individual tags of a tag layout (50, 50') characterised in that the individual tags of the tag layout (50, 50') comprise a plurality of sequenced tags; the plurality of sequenced tags are sequenced along an aisle path in accordance with a sequence list that is accessible to the reader module; and the reader module compares a succession of identified sequenced tags with at least a portion of the accessible sequence list to determine if the succession of sequenced tags is in sequence along the aisle path in accordance with the sequence list, generates a missing tag signal for a malfunctioning sequenced tag when the comparison of the succession of sequenced tags with the sequence list indicates a sequence irregularity in the plurality of sequenced tags, correlates vehicle functionality with the malfunctioning sequenced tag when a missing tag signal is generated, and correlates vehicle functionality with an identified tag in the tag layout (50, 50'), tag-dependent positional data derived from the identified tag in the tag layout, or both; and the vehicle controller controls operational functions of the industrial vehicle hardware in response to: (i) the correlation of vehicle functionality with the malfunctioning sequenced tag when a missing tag signal is generated, (ii) the correlation of vehicle functionality with an identified tag in the tag layout (50, 50'), tag-dependent positional data, or both, (iii) user input at the user interface of the industrial vehicle, or (iv) combinations thereof. the industrial vehicle hardware comprises storage and retrieval hardware and a vehicle drive mechanism; the tag reader and the reader module cooperate to identify individual tags of a tag layout (50, 50') characterised in that the individual tags of the tag layout (50, 50') comprise a plurality of sequenced tags; the plurality of sequenced tags are sequenced along an aisle path in accordance with a sequence list that is accessible to the reader module; and the reader module compares a succession of identified sequenced tags with at least a portion of the accessible sequence list to determine if the succession of sequenced tags is in sequence along the aisle path in accordance with the sequence list, generates a missing tag signal for a malfunctioning sequenced tag when the comparison of the succession of sequenced tags with the sequence list indicates a sequence irregularity in the plurality of sequenced tags, correlates vehicle functionality with the malfunctioning sequenced tag when a missing tag signal is generated, and correlates vehicle functionality with an identified tag in the tag layout (50, 50'), tag-dependent positional data derived from the identified tag in the tag layout, or both; and compares a succession of identified sequenced tags with at least a portion of the accessible sequence list to determine if the succession of sequenced tags is in sequence along the aisle path in accordance with the sequence list, generates a missing tag signal for a malfunctioning sequenced tag when the comparison of the succession of sequenced tags with the sequence list indicates a sequence irregularity in the plurality of sequenced tags, correlates vehicle functionality with the malfunctioning sequenced tag when a missing tag signal is generated, and correlates vehicle functionality with an identified tag in the tag layout (50, 50'), tag-dependent positional data derived from the identified tag in the tag layout, or both; and the vehicle controller controls operational functions of the industrial vehicle hardware in response to: (i) the correlation of vehicle functionality with the malfunctioning sequenced tag when a missing tag signal is generated, (ii) the correlation of vehicle functionality with an identified tag in the tag layout (50, 50'), tag-dependent positional data, or both, (iii) user input at the user interface of the industrial vehicle, or (iv) combinations thereof.