I'm afraid there is not a link I can provide you with that has details of the snacks onboard. However, a list would include:
Pringles (sour cream and onion & original flavours), Mini Chedders (cheese and salt & vinegar), Kit Kat, Mars Twix, peanuts, Fruit & Nut cereal bar, olives, popcorn, Haribo Starmix, Maltesers, Minstrels, Revels, shortbread, snack pack (includes Hula Hoops, Kit Kat, crackers, cheese, paté, serviette and knife).
There is a link to Monarch's onboard menu for Aug-Oct 09
here. It is usually quite nice (even if I do say myself

)