Can anyone help with the following;

I have dates in column B e.g. 01/05/05 (could be lots of dates on the same
day or different days) and times in Column C e.g. 0900,1545 (all 24hour
clock) I want to be able to do a formula that says;

If the time in cell C1 is the first time after 0800 on the same date if it
appears in column B, then I want to see the result of 1 appear in D1.

e.g.

Column B Column C Column D
01/05/05 1045
01/05/05 0930 1
01/05/05 1517
02/05/05 1120 1
02/05/05 1640

Any help would be great!