The partition scheme "" is currently being used to partition one or more tables.

Couldnt drop rogue Partition Scheme due to rogue indexes.

Indexes were not visible through SSMS, but sp_help ‘tablename’ revealed a number of additional indexes, which were based on the partition scheme.

Drop the indexes using DROP INDEX, and rerun sp_help ‘tablename’. This should confirm there are no objects linked to the rogue partition schemes. The rogue partition schemes can then be dropped using DROP PARTITION SCHEME, before dropping the partition functions using DROP PARTITION FUNCTION.

To summarise:

Sp_help ‘tablename’

DROP INDEX IndexName ON TableName for all rogue indexes.

DROP PARTITION SCHEME PartitionScheme

DROP PARTITION FUNCTION PartitionFunction

DROP PARTITION FUNCTION PartitionFunction