In the mail
It was hard to part with these cheerful blocks, but I have put them all out in today’s mail. I ordered an item from the UK last week. The lady said she had shipped the item the same day. I am still waiting, so I have no idea how long my envelope will take to get to England. As for the other 2, you should receive them in a day or two.
I've packaged mine up, in tyvek envelopes with the address on, then outer card backed manilla envelopes with the address on. But got sidetracked making a liberated alphabet and didn't make it to the post office today – it's on the list for tomorrow's shopping trip… I'll ask them about delivery times – depends what 'class' the parcel/letter was sent how long it takes – did she say anything about that?
Send them by regular mail (whatever the default is called) and it will be fine.