SSRS: Format Date Parameter Labels in RS

Recently creating a report with a dataset populated parameter list with INT as the value and DATETIME as the label.

I wanted to have a sensible title along the lines of: Report for date: DD/MMM/YYYY rather than the full nasty datetime. Easy i thought. Just use Parameter!MyDate.Label in a textbox and wrap it with a Format expression. To my chagrin however, i could not get this to work. Doing the following:

=Format(Parameters!MyDate.Label, "dd MMM yyyy")

resulted in a display of dd MMM yyyy. Not what i wanted at all.

Although the label is a DATETIME in the dataset, i wondered whether it was being converted to a string by RS so i tried to explicitly convert it to a date before running the format clause:

=Format(CDate(Parameters!MyDate.Label), "dd MMM yyyy")

Again, no dice but with #Error.

The closest I have been able to get is to just TRIM the label to the 1st 10 characters, which doesn't give me the exact format i'm after and I don't believe is the most robust solution.

=Left(Parameter!MyDate.label,10)

I've posted on the MSDN forums and hope for a response.