If I’ve understood this right, he has breakfast at home, then nursery provide a mid-morning snack such as cucumber and breadsticks, and then lunch at 1pm. That’s all perfectly normal and in line with standard paediatricians' nutritional advice.
NHS recommend 3 meals plus 1 or 2 snacks and about 12oz of milk daily for 2 year olds. Nurseries normally give morning and afternoon snacks, so they’re already at the top end of the recommended intake. Without wishing to be rude, it’s clear that the normal maximum isn’t enough for your child, which suggests this is something to discuss with your health visitor rather than your nursery.
Whilst most nurseries I know do lunch that bit earlier, 1pm is not all that unusual. It’s quite normal for children to eat around 1pm, especially when you consider how many get picked up from nursery or preschool at noon by parents/childminders, etc.
In fact, 1pm might be considered a more sensible time, as it spreads the daily meals more evenly. A 12 noon lunch can leave 6 or more hours before dinner if parents don’t finish work until 5/5.30 then have to commute, pick up from nursery, and drive home before they can even make a start on meal preparations.