Cell Validation (or part thereof...)

[lynxbci]

Hi,
I have a column with completion dates, and i want the user to be able to put a date in the format "Week XX YYYY" where XX is the week no. and YYYY is the year. Is there a way of validating a cell to allow this, without creating a list somewhere with 20 years of week numbers and years?

Thanks in advance

 

[GlennUK]

Before going any further, have you considered having a column for year choice and a column for week number?

 

[lynxbci]

I have considered this, but it is an established spreadsheet and there are 6 date columns in it, that would mean 6 more columns and some re-shuffling, and I was hoping i had missed a 'simple' solution.
Plus having 2 columns means that users have to remember to change a week and the year.......and you know users.

I have written a userform where they can enter the date and it converts it to week number and year, and was hoping that i could stop them typing anything in to the cells at all.