@bellinisurge @HunkyDory69 thank you so much for the suggestions!
I didn’t think of yoghurt lollies, great idea to use up his normal tub leftovers.
I feel relieved knowing I can make my own with UHT too if needed.
He has 2 bottles of multivitamin liquid in the cupboard (Tesco offer) and I’ve stocked up on Weetabix, Cheerios and porridge oats.
I had a great recipe to use up baby porridge making banana snack bites:
Mash 1/2 a banana and mix with 3-4 tablespoons of fine porridge oats
Stir in 2 tablespoons or raisins
Form mixture into small bars (I did flattened blobs)
In the oven on 180 for 10-15 mins until firm ( mine took more like 18)
He loves them and they keep well for snack time. I’m going to try substituting raisins for dried apricots so I can get a few different flavours for him.