Why don't you give him Weetabix? You can give it from 6 months and it's quite filling. And if he's still hungry some wholemeal toast soldiers.
Re the formula - my ds3 is 6 months and I'm finding he is rubbish on his morning bottle - only ever drinks 3-4oz of it so I'm giving him breakfast too. He too is on the Heinz oaty porridge but as soon as the pack has run out it'll be Weetabix!
forgot to say - i give him breakfast about 2 hours after his early morning bottle so he's builtl up an appetite... if i give him toast he tends to play with it and suck it but not eat much of it either - he still likes his soft foods more.
I still give ds a full bottle of milk when he wakes as we don't go downstairs for a couple of hours - then he maybe has a couple of squares of toast but not much else.
If they play with it - i reckon they're not that hungry.
eggy bread is always a favourite - but usually save that for dinner time.
My ds always napped better if he had a full tummy. so even after lunch I would offer him milk and let him drink as much as he wanted.
I'm going to try DD on eggy bread now for lunch!!!
She has (7.5 months)
5am BF (sometimes BF at 3 if she awakes)
8-9am half a weetabix and milk
12-1 lunch 6 cubes of veg or little pot of something I've made and half a banana and 2 tablespoons of greek yoghurt
5.30pm dinner again like lunch
I always offer a BF at 11 and 4pm but sometimes she's on about 5 minutes and starts sucking her thumb instead!
She either has weetabix (which she first didn't liek now loves ) or ready brek all the little packet breakfasts I looked at had far too much sugar in them.