An update.
I should tell you that the school has a large kitchen, food is cooked on site but provided by outside catering company.
Last year when twins started school I did contact the caterers to find out what vegan options were on the menu. There are a few things in the rolling 3 week menu and some things can be adapted but they would end up with jacket potato with salad a bit too frequently and no nice puddings (just boring old fruit).
I like the idea of the twins having school lunch so I don't have to sort out a lunch box! But packed lunch works out cheaper and I know they eat it, whereas school dinners work out a lot more expensive for food they may not eat.
Moving forward to now - I discussed matters with the head of catering on Monday, I wrote to the school and I spoke to the head teacher today.
Firstly, packed lunches will continue to be an option but personally I will work with the caterers to get my children having school dinners some days of the week - for a number of reasons including that those lunches will be "free" and all the other children will be having them.
As there is a large kitchen at the school the head and the caterer both think that food can be put aside for my children, so even if they are at the end of the queue it will not be that all the vegan food has gone AND they believe they can manage to adapt some dishes to be cooked separately. Obviously schools with smaller kitchens may find this more difficult.
The head teacher was quite definite that Vegan children are entitled to be catered for and that this is enshrined in legislation - contrary to the opinions of many who felt the need to comment on this thread.
The problem may be, however that there is insufficient variety on the menu for it to be interesting.
I will be meeting with the caterers to take this forward. As they provide meals to almost 100 Kent schools there may be other vegan children in Kent who could be eating the food.