The k11's are a little bit bouncy anyway because the suspension on them is so light when it's stock (for comfort) and the car itself doesn't weigh much
Like NB said, failed/failing dampeners can be tested by leaning on the corner of the car and seeing how quickly it comes to rest again. It's a part of the MOT so for peace of mind it will be checked the next time it is in. They typically fail because they are leaking, which can be a rust issue or can be if you drive on a lot of cobbled roads or farmland for example. I don't remember having changed mine in the last 10 years