Data Validation for first part of Text string

Hi

I am being provided with a spreadsheet containing among many things, a long list of names.

I need a data validation formula to control the way this data is entered into the spreadsheet. The names must be entered like this: J Armstrong . So I need a rule that says the first 3 characters must be Upper Case/Space/ Upper Case. There is no restriction on the number of characters.

I have seen how something like =AND(CODE(LEFT(Y12,1))>=65,CODE(LEFT(Y12,1))<=90) will ensure the first letter is upper case, but I cannot get the other conditions to combine in the one formula successfully.

Could anyone help on this please?

Thanks

Eoin Joyce