Creeping around....

Have spent time today creeping around the garden trying to snap 4 small tortoiseshell at once on the oregano but they are not co-operating one or two fly away, when it is another sunny day will try again. It will not be tomorrow as rain and thunder is forecast

Think this is a Small White..Artogeia rapae...identifying it by looking up my Collins Gem Guide, if I am wrong please put me right folks