This struck me as a little odd, for two main reasons:
Firstly, there is no mention of the purchase or rental of a bike in the typical example of British household spend, in either recreation categories, or personal transport. Presumably the ONS expects us to don cycle helmets to ride childrens scooters or visit the stables to which we pay our Livery charges, or else just to steal a bike.
Secondly, although I appreciate that visitors to this site as a demographic will spend more than the average on cycling kit, I would have thought that a helmet is far from representative of bike related spend (not to mention contentious, supporting the misconception that helmets are/should-be mandatory) [I'd like to avoid a re-run on that debate, but am aknowledging its existence]
With bargain-bucket helmets available for £20 ranging up to specialist race lids for ~£350, I'd expect the ONS to mark up around £40 for a helmet per household per annum on cycling related spend. Given that the Mrs and I spent a total of £600 on new brakes for the mtbs in January (shiny, shiny Hope kit [supporting UK business too]), and that's hardly going to be the last of the year's purchases, what would you guys consider to be a more realistic value and associated item for the ONS to put in the nations' basket?