I think Almo Nature might have some hamster safe formulas.I know Lily's Kitchen is good as well,although I can't remember any other cat foods in the UK that are high quality but also hamster safe
I might try and organize a list based on what P@H list online at some point.Unfortunately a lot of higher quality cat safe foods aren't hamster safe,often because they include spices(cinnamon is especially common)or in some cases more exotic proteins that are excellent for cats but not so great for hamsters(lamb,quail,pheasant,etc).
Of course,there are general guidelines to follow with any food such as no derivatives,digest,etc(unspecified therefore unsafe biproducts even including "liver" and animal liver),unspecified preservatives(E&C approved is quite likely to be BHA/BHT/ethoxyquin which are known to cause cancer),and of course no artificial dyes or flavors nor should there be any processed sugars or artificial sweeteners(maltodextrin,dextrose,sorbitol,etc).
I'm on the fence about xanthan gum,guar gum,and carrageenan though.I forgot whether or not they're safe for hamsters,but it's likely that they aren't.