Tesco have started invading Japan, so you can get some home style tea at a fair price. They also have custard creams and borbons and real mayonase. Also spotted some brown sauce
www.tesco-japan.com
Cider is a soft drink here but you can get 1 liter cartons of apple juice, add some yeast and have some english cider in about 10 days.
The idea Japanese have of cheese is the same as American, so lame as a55! Sure you can get plastic cheese, soft white stuff and Italian/French offerings. But chedder is expensive and comes in amounts that will only make a sad version of a plowman's.
Baked beans are like 300 yen a tin but I recently found some pale imitations for 100 yen. A good squirt of katsup gets them in order quickly.
Bring gravy granules, or learn how to make it from scratch. The beef here is awesome but sometimes I want some gravy on it
Use Kobe-Busan
食品業として日本最大の製販一体企業 神戸物産 for frozen veg, pizza bases and tortilla breads. Also they have a good selection of imported foods.
Lastly (for now) you can always hit Kaldi
KALDI COFFEE FARM
If you really need a jar of patak's curry paste or some other obscure food item.
And I just remembered. Hit a local indo curry house (normally english speaking) and ask where they buy their lamb. The will usually point you to a local supplier who can not only hit you with lamb (2 kilo for 1,500 yen) but naan bread, pappadoms and other currie goodness.