3 words.
De cath lon.
EDIT. They have a great range of grips THESE are excellent. I have them on one of my Kingpins, they are very comfortable. Good value too.
DOUBLE EDIT. FYI I have bought recently the Brooks leather handle bar grips, but that’s because I’m a ponce and I like saddle and grips to match. Obviously I had to pay the Brooks tax. But, they look soooo nice. They would look smashing on your Brompton.
Thanks - should have had a poke about in the grips bit when I was picking up my skin dessicant on Monday... even had the bike with me!