You should be able to run off a number of batteries.
The description says it only pulls 7W so at 12V that's only about 0.6A.
You could probably run a 7AH 12V SLA (you should get a little over 11 hours) or any number of newer Lithum batteries, such as the battery geek 10-14-88.
The hard part is getting the Lemo connector.
I found some part numbers that may work - you will need to get the actual part number from and pinout Soundfield (should be in the manual).
You will need to make sure you get the polarity right so don't do anything till you either get the manual or talk to Soundfield about the pinout and part number.
FGG.2B.302.CLAD.92 Straight 2 pin
FHG.2B.302.CLAD.92 Right Angle 2 pin
Note sometimes there listed with out periods sometimes there listed without spaces and periods. Lemo always lists with periods, distributors may or may not.
I can't tell from the Lemo part numbers as they are pretty complex and the catalogs are less than intuitive, but here's what I could read from
http://www.lemo.co.uk/product_files/Coax_triax_mixed_en.pdf page 3:
F = Plug
G/H = Striaght; H = Right Angle
G = Alightment Key -> G one indintation
1B,2B,3B = Series Type
302 = Connector Type (i.e. 302 = 2 Pin)
C = Brass Chrome-plated
L = Insulator (appears to always be L)
A = Pin type ( A=Male Solder; C=Male Crimp; etc)
D = Collet Type
92 = cable 0 max
Possible helpful links:
http://www.lemousa.com/techlibrary/index.jsp - catalog index showing various pdf's including assembly guides, suggested cables, etc
http://www.lemousa.com/pdfs/catalog/USA/e_series_assem_elbow.pdf - shows how to assemble
http://www.lemousa.com/pdfs/catalog/USA/e_series_assembly.pdf - shows how to assemble
http://www.powerpod.co.uk/UserGuides/LEMO_PLUGS_INFO-English.pdf - oem sight providing which pn's are supported with their equip.