not sure about the window cleaner but the rest are definite yes.
Cleaning products - you need a clean environment for the children and they make lots of messes to clean. don't forget cleaning stuff for car too
Washing powder - even if you don't wash nappies or mindee's clothes you do need to wash cot bedding, dressing up clothes & doll's clothes, aprons, flannels & towels etc.
toilet roll - we used 1 roll in 1 day last week (I've found the culprit, we've had words!)
cooking ingredients, yes and anything else you buy for planned activities.
Juice - I claim this, although we do drink a lot of plain water too.
Anything you buy that is used for childminding as well as household stuff you need to EITHER claim a percentage (eg 50%) of all purchases or buy separately (eg you might have Fairy non bio for washing kids bedding and Persil for own clothes).
Don't forget all your stationery & stamps, craft items, handwashing soap, anti bac spray, cloths & wipes, gifts & cards for mindee's birthdays & xmas/easter eggs (if you bought these), toys & batteries/charger, toy library/toddler group etc membership & admission fees, toy/dvd rental, library overdue fines, advertising costs, business phone calls (get itemised bill).
Basically claim for ANYTHING you wouldn't have bought if you weren't childminding
40p per mile for any journey taking mindees out or for training courses or to shop for childminding supplies.