Any advise upon the logbook to buy?
Yes: Mine is called MS Excel. Money well spent, as it is very useful also for other purposes! If your authority really insists on paper, then print out every 10 lines or so and glue the printouts into an ordinary notebook from the nearest stationary shop. Our authority in Germany has been perfectly happy with that kind of "logbook" since over ten years. And if nitpicking Germans can accept it, so can everybody else!
EASA will be no different from JAR-FCL in that respect, which also means that nothing needs to be signed in your logbook by anybody. Most of my colleagues do not have a printed logbook any more, just their Excel sheet (or dedicated logbook software on the iPhone or iPad). As I am more old-fashioned, I still have a paper loogbook of the kind, that you get as a free gift from Air BP refuellers if are nice to them and buy their fuel.