.co.uk or .com?

I’d go with the .com unless I were specifically targeting UK players.

com for longterm and reaching us, but harder than uk

No difference to the sandbox. If you are targeting the UK, then go for .co.uk, if you are not targeting geographically, I would go with .com.

Does a .co.uk domain get better rankings in google.co.uk?

Yes. It should anyway. If you do a search for “gambling” on Google and then Google.co.uk, you get similar but different results. The first 5 results are the same between them, but on Google.co.uk there are two .co.uk domains listed on the first page of results where there are none on google.com.

So it would be a good idea to get .com and .co.uk for your domain and have a mirror of your site?

Maybe even get extensions like .de, .nl, .es, .se, etc. etc. for all your translations instead of having all your translated pages on your .com domain?

Well, you may end up with duplicate content issues if you create mirror sites, which is not a good thing with Google. I would suggest picking one direction or the other and sticking with that. It will take you a ton of time to get one URL operating the way you wish, why worry about two?

Both.

Host them on different servers. After 12 months tell us which makes more money.

For UK, I am sitll looking for a portal partner for

casinos gb

or just a page

london casinos

If the sites are in different languages, then that isn’t duplicate content.