4 months of stuff !

like going minimalist but i just recieved my Altura Orkney56 Panniers and they look so small !
im just not sure how im gonna fit it all in there !
i have 56litres of pannier space and 8 litres in the bar bag
what have i forgotten and what essentials have i missed for a 4 month trip round nz in their summer. and more importantly what are the chances of it all fitting , and leaving me some space to get the days food in from the shops !
obviously ill be wearing one set of clothes at any one time but
*cycling kit*
2x fs260 shorts
2x cycling jerseys
2x underarmour warmwear vests
3x socks
1 x polartech fleece
1 x arm warmers
1 x leg warmers
2 x buffs
1 x overshoes
1 x gridlock waterproof
1 x waterproof shorts
1 x spd shoes
*casual kit*
Sandals(probably stored outwith the bags)
1x packable columbia shorts
2x tee shirts
1 x swimming shorts/goggles
*Cooking*
Camping Gaz Twister piezo
cv270 canister
non stick nesting alu pans
ti spork
leatherman blast
matches
Iodine Tabs
*sleeping*
Vaude Taurus 2 {on top of rack in dry bag}
Alpkit wee arric {on top of rack in dry bag}
Karrimor synthetic global traveler 1100(18cms/30cms)[in pannier in dry bag which is also pillow]
*toiletries*
1 x tub chamois cream
1 x small toothpaste
1 x fold up toothbrush from the flight
1 x soap and scrubing net thing
1 x travel towel
*luxuries*
1x mp3 player/small speakers
1x book
1x tarp strapped onto the top of everything for use if we dont fancy the tent or for storing kit under during the night in heavy rain
1x tool kit and small selection of nuts and bolts for panniers , brakes etc
1x small deterrant lock