Out of the tree types of chillies you describe they are going to be pretty easy to distinguish once they begin fruiting. Bells squarish and blocky, Jalapenos, torpedo like and birds the smallest of the three. Whether the Jalapenos grow upwards or down they will still be recognizable. There are many different varieties of Jalapeno.
Bird pepper is a generic term for a number of small fruited types similar to their wild ancestors (Tepin, Bird Aji and Pequin are some of the names these types go by).
But there is a variety of chilli pepper called "birdseye pepper" (Nickys Seeds has them) with longer fruits than the Tepins and bird Ajis. Since your plants came from B&Q I would think they are a variety of some kind.
In the wild bird chillies seeds are distributed by birds, Only mammals can taste the heat in the fruit but not birds. This is because mammalian digestive systems destroy chilli seeds whereas birds don't.
So if you don't want to eat the chilli seeds when preparing them put them out for the birds!
