getdropdownvalue from related module

Hi

I have a dropdown in Leads module that when it converts I want a dropdown value from Leads to be a text value in Contacts, so it's not editable I thought I would be able to use a calculated field in Leads that could copy the value to the Contact using the code below 

getDropdownValue("dropdown_in_leads",related($contacts,"field_in_contacts"))

I have tried swapping them round and as many variations as I can but the dropdown value from the list never goes to contact field.  I have also tried to create a field in Contacts to grab the related dropdown but that doesn't work either.

Anyone know how or if this can be done otherwise I will have to write a logic hook which seems a bit over kill!

Using 9.3 Enterprise.

Any help much appreciated.