I have a Wharfedale Sub Woofer Remote which has minor corrosion in one corner of its very simple PCB.
Leaky AA battery.
I'm making the giant assumption that this is what has stopped it working.

My electronic repair skills (and vision) have atrophied to the point that it'd be better to pay someone else to look at it.

I'm in Auckland - does anyone have any suggestions ?  

PS: Wharfedale, in their design wisdom, made all control via the remote - there are no controls on the sub itself.
As it's usually a set-and-forget (hence the battery problem), a new house tempts me to tweak the settings.