Hi, we are in the same situation. I have a son who will turn six this August(born in 2003), living in DB. Currently my son is going to Sunshine House in DB(we've been in HK less than 2 months), and the princinpal said my son could return to their kindergarten next term. I contacted DMK and they said no, because my son's too old.
I contacted ESF and they said Bradbury is the only ESF option for DB residents(Kennedy is not open to DB residents any more).
I put him on the waiting list for DC(although they told me not to bother), DBIS(more than 70 ahead of us), LIS(around 20 ahead of us) and Bradbury(around 50 ahead of us) recently. Honestly I was quite shocked to see the facilities in LIS, but they have a school bus service to DB and that's good enough for us now.
Thing is that we never know how long the waiting will take. We are very new to HK, and I can't believe how difficult it is to get into a proper "school" in DB.
Oh, I also contacted Delia English Primary School in Mei Foo, and Delia Mankiu English Primary School in Tsing Yi. They are not international schools but subjects are taught in English. The only thing I didn't like about those schools was that they teach Cantonese as a subject every day. The fee is quite low compared to that of those international schools.
Since we are in the same situation, I do hope things will work great for you.