I've not tested this, simply because I do not have a suitable battery, though I can't see there's much to go wrong with it. Boxed in original box.
Hornby Dublo Battery Control Unit - tested - boxed
Hornby model train set Dublo Power Control Unit A3 - untested
Hornby-Dublo 3 Rail Boxed Battery Control Unit
Hornby Dublo 32849 Battery Control Unit – Boxed
Hornby R912 Power Control Unit 220/240v Output 1.1VA 14.2V Used Untested