Just a short add-on from this side of the Channel.
Everything we (controllers, FIS, RAFIS, etc..) say goes onto tape to be examined after an incident. Things we know for sure, because they are confirmed, we tell you (pilots). Things we got through pilots reports, we tell you as reports. Things that are not verified, we tell as such.
For example: When issuing traffic information, I will indicate how I received the altitude information. E.g. "... altitude reported 2000 feet ..." or "... radar indicates altitude 2000 feet ..."
I'm usually the one surviving the incidents, so I get to answer the attorneys questions. That's the way it works over here, it can't be much different over there.
Never the less, given the technology used nowadays you can take all of those values as sufficient for VFR operation.
Keep them in the air, FR