Not quite on holiday yet. Ali, so sorry about Peter. It sounds dreadful. It's so awful when they are miserable - particularly when things were going so well. Is he very sucky as well? (That could be a sign of reflux, even if he's not puking).
Dorothy was unsettled, very windy and puking. She didn't have red cheeks, dodgy nappies or anything else, so I can't help you on that at all, I'm afraid. But whenever I eat tomatoes or dairy (not often!), she gets really unsettled and pukes. I have had butter in cakes and things and that seems to be fine. Also goats cheese and milk. Can you believe we are going to Normandy, home of Camembert and Pont L'eveque, and I can't have any of it?
Other things you can do for reflux (silent or otherwise) are sit them up after feeds, don't jostle them, give them dummies, raise their cots on an angle, feed one boob at a time. (We are doing Gina, but feeding 7,8, 10,11, 2,3 etc.)
Probably teaching my grandmother to suck eggs, but if you give up dairy, remember to take a Calcium supplement.
Um, the other thing it could be is teeth. They may not be about to come through, but could be moving around in his mouth. I think this is what was wrong with Dorothy this week (when she did have glowing cheeks). If you Calpol him at night, does he calm down? If so, it could be pain.