Quartz digital processor leak?

I have an Aqualisa Quartz digital shower with a grey processor unit mounted in an airing cupboard next to the shower cubicle. It is a few months out of its 5 year warranty, and has developed a leak which we only noticed when water came pouring through a light fitting in the kitchen below. Is there likely to be an obvoius component that may well have failed? ie. seal, 'o' ring or whatever? Been onto Aqualisa who want £260 to fix! Thanks.

MartinB
February 2012