I got this little 3D printed accessory for my Brompton on the AliExpress website. It cost €19.63 for the gloss black version including delivery to Ireland. Although it bears a B logo it’s not an official Brompton product. The finish is a bit rough and ready, otherwise it’s more than up to the job. (I paid for this product - the video is not sponsored) Link here - https://a.aliexpress.com/_EG45fPH. The bag is the Halfords Handlebar Bag which cost around €18.