Battery charging problems!

Markey Mark

Can anybody help? I have just returned to my Knaus van to find leisure battery nearly flat and no indication on control panel that anything is charging from the electric hook up although the symbol for the charger is lit up but not the 2 battery symbols.
I have got power in the mains plugs but lights were getting a bit dim. Am I also being a bit dim, could there be a simple solution? The charger is a Calira Sealine LG 616-DS/IU that was fitted from new in 2007. Does anybody have experience of the reliability
of these auto switching type of chargers? Is there a simple test I could do? The leisure battery is nearly flat but hopefully my van battery will be ok to drive off tmrw.