This is the Rodipet mix. I still use the junior version even though our hamster is senior! He wasn't so keen on the senior mix as it had a lot more herbs in. With both mixes I buy two at the same time to a) save on postage and b) means I don't run out - I order more when I get down to opening the last pack.
https://www.rodipet.co.uk/pet-foods/...nior-500g.html
https://www.zooplus.co.uk/shop/small...er_food/620085
I get these for freeze dried chicken
https://www.amazon.co.uk/gp/product/...?ie=UTF8&psc=1
This is the Science Selective food
https://www.amazon.co.uk/Supreme-Pet...grocery&sr=8-1
Not sure what you're using at the moment - you mentioned larger pieces. If it's Harry Hamster, that is fine too, as long as she eats it. It contains everything needed.