Lights warning 'beep' and lamp

I fitted one of the auto light switches/kits available from Ebay to my Mk1 VRS to 'upgrade it' to auto lamps. My car has the factory Xenon lamps. 

Easy enough fitment - remove switch surround from the new switch and fit into the existing fabia one, Plugs in to the existing harness and then run the light sensor to the corner of the dash. Simple enough.

It all works as it should - I have auto lamps and also coming home/leaving home lights when you lock or unlock the car at night - great.

However it has also triggered a high pitched 'beep' every few minutes and a warning lamp on the dash showing a lamp symbol and and exclamation mark? So basically my question is what have I messed up!?

I've put the original switch back in for now but if there was a way to make the auto lamps work without the error/beep that would be really helpful

All the Best.