Poisoned Pen Press (American I think) still publish them all. The covers aren't as nice but they are available from on-line things like The Book Depository etc should you want physical copies at some point. (I curse them because I have the first 4 in the original publishers and have had to get the rest as poisoned pen press and the buggers are a different size and design and everything. It drives me slightly batty and I am going to have to get copies of the first 4 in the new design as well.)