If this really is the service you personally are carrying out then yes it's good value SHOULD ALL THOSE EXTRAS REQUIRE DOING. If no rads need replacing, if the system is fairly standard, and if the pump is fine, then it looks rather costly. My personal experience of BG powerflushes has involved the guy plumbing in the unit and sitting back with copious cups of tea for 3 -4 hours. I'm sorry to generalise, and I'm sure there are also good responsible engineers amongst BG's crew, but I'm rather cynical towards any firm that demands targets of their engineers that inevitably lead to short cuts.