a basis toad ai606 will be £220ish fitted, you can get extra stuff like glass break sensors, proxy sensors (if you want to annoy your neighbours), headlights (wont really work on a k11), door poppers (need addition bits for a micra).
I know a excellent installer who does all my cars for me, he can do all alarms (toad, sigma, clifford, etc). Were in the west midlands are you and i will ask if he covers that far.