Id suggest Zodiark.English is the main spoken language on this server.There's a lot of uk players here and the ones that arent from uk generally have quite a good level of english too.
Its a very friendly and active community.Daily hunt trains.You'll see plenty of people about.Getting into a decent fc shouldnt be an issue and the market board prices are genuinly quite good.
I wouldnt reccomend Twintania in its current state.Its a new server and you get the bonus yes.However its flooded with bots and rmt seller accounts.Most of the rmt sellers advertising on other servers have been comeing from there.They use Twintania to make accounts and then use world visit to advertise on other servers.There's also the issue with the market there.Right now its really bad.Because whats happened is a bunch of older players have moved there and set all the prices to rediculous amounts to try and rip off new players.You can world visit to go to other market boards but it shouldnt be a situation where you have to do this any time you want to purchase something.

Odin also has a large uk playerbase being the main english speaking server.However its very congested right now meaning you probably cant make a character there.There hunt scene is also the most toxic out of all the data centres so if you have an interest in future hunting its probably the worst server to go to.
The server is also highly raid focused with probably the best player skill average of all the eu servers on that database.So if raiding is your end game goal you'll likely want to move there eventually.

Phoenix seems to have quite a friendly playerbase.Not sure about the level of activity there though or the main language.

Cant say much about Shiva or Lich.I think both these servers have the highest german playerbase?

As for the other eu data centre i havent heard great things about most those servers.All i know is if you do switch to that datacentre avoid moogle server at all costs.