Custom Despatch Note - add option to skip mailmerge field AND/OR allow merge field for entire address block

On Custom Despatch notes you can add in the various mailmerge fields for Name, Company, Address Line 1, Address Line 2 etc. However if the customer doesn't have a Company or Address Line 2 then those lines are left blank on the despatch note and look something like this:

John Smith

123 Fake Street

London
SW19 2PT

That doesn't look great and should look like:

John Smith
123 Fake Street
London
SW19 2PT