Baby used to sleep through the night but now waking?

My baby son is nearly 5 months old. He started to sleep through the night when he was about 3 months old. He would sleep for about 10 hours straight through. Recently he started waking twice in the night for a feed. He was also showing other signs of being ready to start weaning such as sucking his hands, not being satisfied after drinking a full bottle, getting hungry after just 2 hours since his last feed etc etc. I wanted to wait until 6 months to start weaning as per the current advise from health care experts so I switched him from SMA Gold Formula to SMA Hungrier Baby Formula. I hoped this could delay weaning. It made no difference at all and my baby just guzzled it all down as if it were the same milk. My health visitor suggested I started weaning as my baby was obviously a hungry baby and ready to wean. Last week I started with baby rice but it wasn't satisfying him. I am now giving him approximately 10 teaspoons of fruit/vegetable puree at lunchtime and the same amount of baby rice in the evening as well as all his usual bottles (approx 6 bottles throughout 24hrs 9oz each - SMA Hungrier Baby Formula). Despite all this my baby is still waking up hungry at night. Has anyone else experienced this?