Windsor Framework and sending to NI via the Post Office

[mod81]

I received an email from Royal Mail regarding telling me that I will need to provide additional information online when booking parcels for delivery to NI after 1st May due to the Windsor framework coming into effect.

A private individual in Great Britain sending a parcel for personal use to a private individual in Northern Ireland

For each item we will need a description, weight, value (where known) and goods categorisation (where known) based on the description you provide

All the guidance I can find about what to do after 1st May is for buying postage online.  Were as for items that are large letter sizes I would usually just stick the appropriate amount of stamps and drop it off at the post office.  Is that going to be possible after 1st May or will I be forced in to buying postage through the RM website so I can give them all the size, weight etc.
Or can i just stick a customs form on the outside of the package with the info hand written on it like I would do for any packages going overseas?

The Royal Mail website has no mention of what to do for none online postage to NI, like they assume everyone just buys postage labels online and no one uses stamps or pays for postage at the PO anymore.

[wyntersemporium]

Or not send to NI at all block it from buying. Had loads of orders from there.  Now hardly any. 

[mod81]

I sold something to NI only recently so I do still get sales going there, so I don't want to cut them off. As Ebay sales have been down in general recently so I don't want to be taking away millions of potential customers by blocking NI buyers.

But as usual the bringing in of new regulations have been handled terribly by the UK gov and the businesses, I can guarantee come 1st may there will be 1000s of parcels going to NI which won't have the correct paperwork and causing delays to delivery.