I recall a Willesden Winter Full-Value Boudicca 200 a few years ago: we started just before dawn and went via the airport perimeter road as there was a touch of frost about. Cafe stops all the way apart from the first stop at Buntingford, when Assassin's flask of hot chocolate was deployed, along with cherry bakewells.
There used to be a cafe in Potton, sadly long gone, so as suggested upthread, an early cafe break in Buntingford, Lindsay's Bakery in Potton for takeaway hot drinks and cake [among many goodies they have elephant's footprints - the Audax Food of Champions], Green Welly = enormous portions for a late lunch, A14 services, then a pub stop - I suggest the Queens Head in Littlebury. Depends on timing of course, but the QH re-opens for food on 28th at 6pm - a mere 27km from the finish. Or crack on and eat in Dunmow [at the Angel and Harp?] once we've finished.
Meet from 07:00 at the Paradise in Dunmow [by the War Memorial in the middle of the town], starting at 08:00 so we'd have until 22:00 to get back on a 14 hour schedule!