Either decide you want personal customers or not.
I have tried at length to import my Address Book following your instructions after being re-directed several times between sites. Using the exported file from OLP. The only "Import" option is via orders which is no use as it informs me that several fields are not complete; that is the fields your programme exported. The screenshots you show do not represent the screens provided when following your instructions. Abomination of a "Service" and clearly only interested in Business Customers.
Business customers don't fare much better I can assure you. Part of the problem seems to be ever moving goal posts, RoyalMail is such a big organisation that different parts of the operation seem to do do things without telling the rest. Each has their own idea about how things should be done and every now and then someone gets the go ahead to throw out everything and start again. The trouble is just like the government every IT project from RoyalMail takes years to implement, costs 5x more than it should and is designed to meet the needs of the internal departments instead of customers.
I'm sure the developers of Click & Drop are keen on building it but their hands are tied behind their backs. They can only do what management committee agree on and their are stuck with having to link to an ancient SAP system that is as slow as a paralysed snail at busy times.