I wouldn't treat against scab or worms unless I needed too. treating as a precaution for these kinds of parasites only increases the chances of resistance.
And yes it is a bad year for flies, just found one of my ewes with Pink Eye in one of er eyes.... Looks quite frightening, but she is alright and mightily unhappy about being in a pen on her own (with her lambs)... but just put oointment into her eyes, repeat tomorrow and then see if she manages to stay in another day for a further treatment..