I'm creating a data input sheet for thousands of entries, and i want to
restrict the input cell for postcode to the following formats;

wf10 4nr = 2 letters followed by 2 numbers followed by a space
followed by 1 number then 2letters

or;

ln5 4de = 2 letters followed by 1 number followed by a space
followed by 1 number then two letters

so therefore if the data inputter types in anything other than the formats
shown above, a validation message will appear.

Can anyone help me?