Cell Protection
 

I have created 5 columns - date 1 to 5 all with offset valdiation in them
being validated against the preceding date i.e. Date1 = filter from
validation list of dates, Date2 = offset validation against Date1 so that
Date2 = Date1 and so forth up to Date5. Protecting the cells (i.e. Format
cells Protection Unlocked) then protecting the sheet prevenets the user
from entering data into Date2 (for example) where Date1 has been selected as
a date, however if you jump to Date4 which doesnt have a preceding date in
Date3, this then allows the user to manually type anything in the box! Which
is my problem, I dont want a user to be able to manually type anything in any
boxes.

Thanks