minding school age through summer

Hi whilst i am waiting to register to childmind, i was thinking about taking 8 and up during the school hols.
now i know you dont have to be registered to have over 8's but what do you think about this?
Will i get the kids?
I am NNEB trained and i am going to do the voluntary register before i get full registered because i have been asked to look after my son's now ex girlfriends baby three days a week.
What do you think ofsted will say regarding me haveing school kids in the summer?
Hey Ho what to do!!!!!!!!!!