Aidyn was on more than 1L of formula for ages... I think he averaged around 1.25 litres most days at Miles's age, sometimes more - but usually not less than that.
I also always gave him a dreamfeed bottle at about 10pm at night (or whenever I was about to head to bed) and this would tide him over until usually 7am (or thereabouts). Sometimes I would give him a morning bottle at 5 or 6am and he would go straight back to sleep again for another few hours (*sigh* those were the days!)

I have never heard that bubs are not meant to have more than 1L of formula per day, .. I actually think it may be worth giving him an extra bottle during the night to see if it will help him sleep through till the morning.

Goodluck Sal, I hope you get a decent nights sleep soon!!