Ugh just lost my reply! Fine to leave baby food out overnight- our hamster did that too. Ate a bit then ate the rest during the night. Porridge - make with water - milk not good for them. Yes baby good harder to find - pandemic shortages and some not made any more. I used to get them from Tesco or Sainsbury’s (who hardly have any choice of suitable ones) and sometimes from Amazon.
Tesco has this one (only suitable savoury one I could find),
Hipp Organic Carrot & Peas Baby Food 4+ Month 125G - Tesco Groceries
Sainsbury also sell that one - plus this one - which was all our hamsters favourites.
https://www.sainsburys.co.uk/gol-ui/...--chicken-125g