None - but keep checking...
ARCADIA Overtank Luminaire 2x25w T8 30"

Now - £55
The Overtank luminaire ia a stylish unit,manufactured from corrosion resistant ,silver powder- coated ,aluminium,and of a profile similar to the already Series 3 metal halide pendant.
This luminaire is suitable to fit tanks or aquariums of up to 915mm in overall length with a tank wall thickness of no more then 12mm.
A stylish alternative to traditional aquarium hoods.
Unlike a conventional aquarium hood, the overtank luminaire is raised clear from the top of the tank on adjustable legs, which attach securely onto the aquarium or tank side walls. The luminaire can then be tilted back to a near vertical position to allow easy access to the aquarium when required.
The open top allows plant growth beyond the water surface, twin lamps are supplied, one blue and one white, for improved plant and coral growth, in-built reflectors to maximise light output, adjustable mounting brackets, and anti UV transmitting shield.