Healthy start vouchers should be able to purchase milk alternatives not just cows milk

I feel we should be fighting for this change to be able to provide the right milk alternatives for children who are in low income families. And its important for their development just as much as cows milk.
I am a single mother who has a child who needs milk alternatives in her diet due to having a milk allergy. I receive healthy start vouchers and these do not allow to buy milk alternatives with the vouchers i really think that they should be used to purchase milk alternatives as well as cows milk, fruit, veg and pulses. Milk alternatives are similar prices to cows milk but come in a 2 litre carton which lasts up to 3 days depending on how much a child drinks. When you are on a very low income it gets expensive and its essential your child has this as a source of nutrition. I would be grateful if you can take time to consider this as a change to healthy start vouchers as this is a must in so many young children's lives and many of these children are of low income families in receipt of these vouchers.