"Graham cracker" chocolate chip muffins

I came across a recipe the other day for Graham cracker chocolate chip muffins and they looked and sounded delicious. I couldn't get hold of Graham crackers here in the UK, so I had to resort to digestive biscuits in this recipe adaptation. I have made them dairy-free, and am hoping that I haven't lost too much of the taste of the original recipe in the process.

Ingredients

2 cups of plain flour
1tbsp baking powder
1/2tsp salt
1/2 cup sugar
1 cup of digestive biscuit crumbs
1 cup sweetened soya milk
1/3 cup sunflower oil
1 large egg
2tsp vanilla extract
3/4 cup dairy free "milk" chocolate chips

topping:
1/4 cup flour
1/4 cup light brown soft sugar
1/4 cup golden granulated sugar
1/2 cup digestive biscuit crumbs
3/4tsp cinnamon
3tbsp soya margarine, melted

Method 

Mix flour, crumbs, baking powder, salt and sugar in a large bowl.
Mix oil, milk, egg and vanilla in a jug.
Add the wet to the dry mix and stir well to combine.
Finally add the chocolate chips and mix in.

In a smaller bowl, mix the topping ingredients together. The mix should be crumbly. I have changed the ingredient quantities from the original, as my version of the original was really gloopy. It must be due to the water content of the margarine.

I made 16 muffins in lined muffin tins with this quantity of mix, with each case 2/3 full of mix. I then added a teaspoon of the crumbly topping to each muffin and baked at 190c (fan) for around 15 minutes until they were cooked through. They smell amazing. They taste delicious, especially while still warm!