This morning I had a tootle round Boudicca's Revenge 100km (reversed), with a few bonus kms checking out some interesting alternative routes. 119km in total for me. (107km on the brevet, usually more like 110 depending on how closely you stick to the routesheet.)
The Mohak Café in Haslingfield haven't finalised their holiday opening times yet and I was told they may possibly shut between Christmas and New Year. An alternative venue might be Day's farm shop and café at Newton, a handfull of kms before you get to Haslingfield (which was at pretty much 50km for me). They are open normal hours from 27th Dec. There are many, many alternative routes along/parallel with the Cam valley, depending on how you feel about hills/grotty lanes/the old A11.
In Buntingford, the Coffee Shop will be open after Christmas, but with slightly reduced opening hours. It's likely we'll be there early afternoon. There's also a branch of Days here, but I can't see a pub that serves food, so I reckon Haslingfield/Newton will be the main brunch/lunch stop at just under half-way, with a tea and cake stop in Buntingford.
The very leaky lanes from Buntingford to Manuden were as waterlogged as ever - lots of minor floods, gravel, mud and potholes to keep you alert! I'm reckoning on a 7 hour ride, (8h33 allowed, at 12.5kph!) with two leisurely feed stops, so we should be round in daylight.