I agree. How anyone come up with that price for those batteries alludes me.As for value, well no contest. A new Kalkoff 17Ah battery costs in the region of £800 - totally ludicrous -
I'm on my second as well but the first failure was on warranty. The second one has been flawless so far though so maybe the issue has been (is being) resolved).
If I bought another battery it would be a well researched one for a few hundred squids.