Post office

I have never used Royal Mail / Post Office to send larger packages like for the postal application. Not even sure what the difference is between courier and other normal post?

Will go to the local post office and ask but I thought maybe somebody could tell what kind of packaging/service to use.

There seem to be a few options Special Delivery / Signed for / Next day whatever. There is an option to include self addressed envelope.

Does one buy the packaging at the post office there then stuff docs into it and hand it to them for postage right there?

And the pre paid self addressed envelope we can include - on what basis is postage charged? Since it is empty at that point.

What is most appropriate for Tier 1 postal application for self plus wife together?

Can someone who knows this stuff better please shed some light.

Generally special delivery costs you approx 7 £ and it also insured to 500£ value. You can include prepaid special delivery for your return documents and that also charges you 7£ approx and it will be up to 500gm i believe. So no issues. I have been using same service for my 2 tier1 extensions, And no issues.