You want to Google search the forum, there have been some threads about the same here already. You are not new here any longer so maybe you have already seen them, but it is worth a look.
GIFFGAFF will be your friend.
Bought one via amazon. got it in 3 days.
Bought a second one directly from their website.
No stress for ID verification and so on....
Just remember to make a phone call once a while and a top up as well.
That's why I say Google search, irrelvant is a comment like yours which obvious indicate that you are not reading what I wrote and your other replies indicate that you are not satisfied to be here, so just move away if that is the case.
Oh, and while I am on it, you should post in the proper forums to get valid answers AND maybe look in these forums for existing answers.
Yeah, giff gaff only have uk numbers.
But they do not make proof of adress or indentity, as long as you top up credit for calls with a debit or credit card.
Are you interested in having a phone number from another europe country?
Try Onesimcard.com
You can buy different kind of sim card. The Universal sim gives you a EU and USA number. and you can buy an extra UK number for the same sim.
lycamobile or Lebara will give you a UK number and if you buy a bundle for £15 per month you can receive and make calls free in Europe. Plus you can call 40 countries inclusive of your minutes whilst roaming for now. Brexit dependant.