Thank you so much Fate I felt such relief to see I'd had a reply!
Your response has been really helpful as well 
We had a really bad night of sleep last night, I think I only managed 1.5 hours of sleep as I was up and down so much so I've been trying really hard to get his naps in today but again its been a particularly dreadful day nap wise I usually aim for 2 naps a day and between them tend to manage to get 2.5 - 3 hrs between the two naps.
I've noted down how the day has gone up until now;
Woke up properly for the day at 6.30
Breastfed @ 6.50 - only 2 mins
Porridge mixed with formula milk and 1oz of formula milk in dolby cup - didn't drink much of the milk
BF @ 8.33 - 7 mins
Nap at 8.54 but woke after only 40 mins.
Breastfed @ 11.20 - 10 mins
Tried to get off for a nap @ 11.30 in the sling but after 30 mins no luck and gave up when he started to get frustrated.
Lunch / 1oz of formula milk @ 12.00 - ate lunch and drank all milk
Nap @ 1.44 but woke after only 20 mins
Breastfed @ 2.27 - 17 mins
Saw your post while BF @ 2.27 so came downstairs after feed and offered water which he took and gave him some fruit as an afternoon snack which I wouldn't normally / hadn't realised he might need.
He usually does want another Bfeed some where around 4ish and then we have Dinner / bedtime routine etc.
But looking at your list compared to mine I agree he isn't getting as much milk as he obviously should.
He never has accepted bottles, so we waited until he started on food and tried him on formula with a cup which he will now take.
I ordered a NUK 5oz trainer cup which has actually arrived today and thats what I gave him the water in and he was happily drinking away from it so I think I will start offering him water now at meal times instead of formula and will ensure I'm breast feeding him for longer in the day and if he has a short feed I'm going to make sure I'm offering him the breast again much sooner.
He has seem contented enough in the day with what he's been getting but I suppose thats because he is making up for it by feeding in the night.
DH has finished early today so has managed to get him off for a nap @ 4 so fingers crossed its a decent stretch!
Thank you again for your reply its given me a much better idea of where to start, even if I do feel awful thinking I've not been giving him enough of what he needs I'm glad I now know and can do something about it.