To be honest, in this Strawberry Trifle recipe there's really no benefit to making your own homemade custard (unless of course, you really, reeeeally want to - in which case, try this recipe!). As long as you use a good quality store-bought custard (like Pauls Double Thick Custard), there's no flavour difference at all... so save yourself some time and effort and use store-bought!