Is that your price or the seller’s? For a post 2014 (longer wheelbase) 6sp with nothing missing and nothing broken, cracked or rusted, £400 is a bargain and a half.
I bought a VGC 3sp in port talbot last year for £400, and considered it a great deal (I was in the area anyway). You’ll be hard pressed to fine a well cared for modern Brompton 6sp for under £650 in London, £600 with some luck.
Is that your price or the seller’s? For a post 2014 (longer wheelbase) 6sp with nothing missing and nothing broken, cracked or rusted, £400 is a bargain and a half.