There is no need (or process that I am aware of) for getting an official certification of the equivalency of your degree with a UK degree. (Update: It turns out there is a process; see the updated question). If you graduated from a well-known University the employer will have heard of it; if not, you could try looking at the German "anabin" site (I think google translate makes a fair fist of it), to see if the Germans have declared your university equivalent to a German one (which will be accepted as the equivalent of an English one).
In general UK employers are less interested in your degree, than in your experience. If you have just graduated, you will find it very hard to find a job.
I think you are going to need pretty good English (B1 at least, and preferably B2) to find a job in England (unless you have outstanding experience). Again, the formal certification is less important than how easily your potential employer can read your application, and how easy your interviewer finds it to communicate with you.