Yeah, usable, just far far from ideal. There are actually a couple of things you could do. Its not great, but you can pay £15 to get some springs changed over from spares to a set of bocks, Wait, look at alternative brands (PJ have best support tho), or, I duno. I think you would need to downgrade at some point just to get yourself going so maybe buy some springs and change them yourself then when you get better change them to the higher ones. But +30kg is still quite a lot. And..if you dont get on with it you have spent a fair amount more.
And yup, sarah is proof. hope you get some new ones soon, what springs were you after?