Not tried frozen mash yet but think I will give it a go for quick fish / cottage pie.
I'm a recent convert to Iceland, I must admit, after years of dismissing it as the home of processed beige crap. I stocked up yesterday and bought: frozen spinach, frozen green beans (tried last night, not bad. Not quite the same texture as fresh but good enough when fresh not in season), frozen cauli rice (I do mself a pouch of this when the rest of the family has rice), frozen peas, variety of frozen berries, 3 packs frozen fish (depending what I'm cooking, I usually thaw and cook as fresh but sometimes stick white fish straight in the oven from frozen), frozen king prawns, frozen croissants, big tub of Longley farm double cream & big tub full fat greek yoghurt. (And some frozen Greggs steak & cheese rolls for DS as pre-swimming fuel 😄)
I also always keep frozen breadcrumbs (homemde -blitz any leftover bread), frozen chopped chilli & coriander, frozen sweetcorn, M&S frozen edamame, broad bean & pea mix (love this in salads - just cover with boiling water to thaw while prepping salad leaves, spring onion & chilli & crumble over some feta). I use garlic & ginger paste in a jar from local oriental shop but will look out for those cubes!
Not keen on frozen carrots or broccoli but tried the Iceland (I think?) frozen cauliflower & broccoli cheese with our Sunday lunch and will definitely buy again as a quick and easy side.