Is this the one?
http://www.ctek.com/gb/en/chargers/MXS%205.0
CCA does concern me on deep cycles, from the car audio world people tend to run split charge with them only running amps off the deep cycle - not overly practical in a light weight car, plus it doesn't need that much continuous power!
The bosch is still OK. If I charge it then it stays OK for a while, just takes less time now before it does go flat again.