Don't worry, my son in P1. Both English and Chinese are above average. Some other classmate from Kentville are also perform quite well. Most Kentville kids will have good performance in P1.
My son was graduated before 2 years. He is a P.2 student and studies in a English primary school.
I don't feel 英文成績差 in Kentville. Although they don't have foreigner to teach English, their English level is not low.
Even my home did not use any maid, he likes to talk to his teachers by English.
Don't worry about English level if you choose Kentville.