As a kid, the whole stalking/assasination of Dr. Benn freaked me out !
I can hardly recall any details at all, but i recall there being this insect-oid robot assassin, who followed them for several episodes and eventually managed to kill Dr. Benn with a syringe filled with poison or something ? It was well moody and the robot looked kinda freaky if i recall ?
Also didn't it get all dream like and super depressing for a while when they went into a black hole and couldn't get out for ages ?
Might be wrong on the details, but this show was among my VERY favourites as a child :)