On 29 June, the source wrote (citation):

In this release of data, the earliest period open to revision is January 1997 as this dataset contains annual updates that will be included in the Blue Book due to be published on 31 July 2018 (the reference year and the last base year for the index have been moved to 2016).

We have revised existing series and updated their unit-descriptor metadata where necessary. Properties are otherwise unchanged (see related article).

The series reside in the historical catalog (United Kingdom » Industry » Index of Services » Monthly | Annual) and include, for example:

• ONSS2KVM.IGBR = Distribution [G], (Index Ch. Vol. 2016=100, SA)
• ONSS2C6M.IGBR = Pension funding [65.3], (Ch. Vol. % M/M 3-mo MA, SA)
• ONSS226A.IGBR = Retail trade except motor vehicles and motorcycles [47], (Ch. Vol. % Y/Y)

Because catalog locations are subject to change, the upper-right search box on DataBuffet.com provides a "find in catalog" mode that accepts a mnemonic.