I've got the 1.2 also, fitted 17" wheels to it and have noticed the wheels sit closer to the arches at the rear compared to the front. Don't think there's any adjustable dampers available on there own - only coilovers. Plenty of sports dampers out there, shorter and uprated ready for lowering springs. If you could return the FK kit and get your money back you could get an adjustable coilover set for 300 to £500. Or you could get an Eibach Sportline kit which consists of Bilstein B12 dampers and matched Eibach springs - lowers 45mm rear and 55mm front I think. Plenty options out there!
Did you only get lowering springs or was it springs and shocks?
P.s lowering springs with standard shocks is a quick way to ruin your standard shocks