WD, in my opinion your clock is some kind of "project" that has a English Eureka "short" movement. I have collected Eurekas for over 20 years and have not (yet) seen a German made one with the short movement (balance wheel behind the dial). All have been what is referred to as a "tall" movement. I'm attaching a photo of one to show the difference. The English Eurekas had both the short and tall versions, nearly 6,000 short ones and a little over 4,000 of the tall ones were made. I have constructed a database for these clocks that shows short movement serial numbers from No. 22 to No. 5696, and tall movement serial numbers from No. 6181 to No. 10538. I have documented 164 of these clocks to date, and thus far there is no overlap between the two types.
The English "short" movements usually did not have the serial number or patent info stamped into the plates (a few do on the back plate), but on a small plaque that is fitted either to the back plate with the screw seen in the center of the plate, or to the front for those having an open (annular) dial. A photo is attached showing the latter. The "Cromwell" English lantern clock model has the serial number engraved in the chapter ring at the 6:00 position, and no ID on the short movement. With regard to Les' comment about English movements without serial numbers, the only ones I have seen thus far with no serial number are the short movements which evidently have lost their ID plaque or were with the Cromwell models; the tall movement versions all have the ID info and serial number engraved into the front plate below the balance bearing.
The operating voltage for both the English and German versions is 1.5 volts. When properly set up they will run about a year on a single "D" cell. I set mine up with two "D" cells in parallel and they will run about 2-1/2 years that way.
The transformer arrangement in the base of your clock appears to be original to the project, but is not original Eureka. Thus far I have not seen any original English or German Eureka being powered by anything other than batteries. The balance spring appears to be complete but badly tangled up, that can probably be returned to normal shape.
For repair info (and parts such as the silver contact leafs and balance spring) you should check Peter Smith's Bulle and Eureka site a
http://www.horologix.com. He has photo examples showing restoration and repairs.