Knowing what Aikido is and its origins are one thing but more important is how and where we practice.

Commonly in the U.K. practice takes place in sports halls, gyms or community centres though there are some that have their own place. 

Aikido classes are usually run through clubs often with one instructor as its head.  Sometimes there are other instructors who will take classes also. 

Other than Classes there are Special courses with guest instructors which give the chance to practice other people and forge friendships.

The most important thing to do when you first start is familiarize themselves with aikido etiquette. Remember It is OK to make mistakes with this, one of the seniors will guide you.