Looks like the OP's figure achieved is (just) within the range given, though I still wonder how many people actually calculate their mpg (if at all, rather just relying upon the trip computer, which aren't accurate) before inputting them on the website.

Given the OP says they don't have a heavy right foot, you have to wonder how others can achieve the 70mpg+ that some do, even factoring in them almost solely driving on motorways/dual carriageways at 55-70 mph. I doubt if fuel choice (premium brand or supermarket) makes that much of a difference either.

I also wonder if not following the manufacturer's guidance when initially running in the car when new affects the mpg later on its life, as it often is said to affect performance. Obviously in this case, the OP cannot be at fault as they bought a 3yo car, so they have no idea what the original owner did during the first few thousand miles of ownership.

Maybe there is a fault with the car, possibly associated with it not being properly run-in, but maybe something else entirely. I'm presuming that, as the OP achieved a far high mpg with a similar-engined car before, that they are not doing lots of short journeys from cold, which could have a serious affect on mpg, especially with diesels.

A change in the type of driving done can make a huge difference to mpg, especially as diesels are very poor on that score until they get warmed up, which takes (if I recall correctly) up to 10 minutes, rather than the 2-5 on petrol-engined cars.

Had a 118d for over 5 years and averaged 47 mpg in mixed motoring. Personally although it was nowhere near the official average I was happy, having read up before I bought it it matched what other owners were getting.

The 116d may have better figures but its still pulling the same weight so to expect much better figures is unrealistic.

The OP was clearly living on a different planet expecting 70+ mpg. They need to get a reality check.

So why the hell are BMW allowed to claim an average consumption of 74.3 mpg when this would appear to be only a theoretical figure that no one in the real world can ever achieve?

BMW are not claiming your car can or will do 74.3 mpg. Read the brochure or manual, it will clearly tell you that the figures are only for comparrison between models and are not figures you can expect to match. All manufacturers say exactly the same because all manufacturers are required to quote (by law) figures obtained by the same testing method. If they quoted different figures they would be prosecuted.

Are you actually aware how the figures are obtained. Its in a lab on a rolling road where there is no wind resistance, no corners, no hills, no pesky other traffic forcing you to slow down. It is not representative of the real world thus you cannot expect to get anywhere near the figures quoted in the real world.

Years ago you could get within 10% of the quoted figures but as time has gone by all manufacturers have got smarter at producing cars that give better official figures but do not give better mpg in the real world. My current car, a Seat Leon TSi does about 17% less than the official, the wifes Nissan Note about 29% under. But we are relaiistic and do our research and the figures we get are what we expected having looked at Honest John Real MPG amongst other sources.

The upside is (for the time being) the low VED you pay. If you paid VED based on the realistic mpg (and resulting CO) it would be far higher than the amount you pay now. Myself and the wife would be paying about £130 per car, as it is one is £30 and the other is zero.

But most buyers simply see the quoted figures and expect to get the quoted mpg. Stupidity exceeds reality everytime.

What type of driving do you do. Is it long motorway trips or short stop start trips.

Reason I ask is like all modern diesels your 116D has a DPF and if its trying to regenerate your mpg will be reduced. Doing short trips will require more regens and your mpg will suffer. During a regen my 1 series diesel would indicate about 35 mpg on the dash.

But don't rely on the dash display, my 1 series diesel woul show an average of 53 mpg in mixed motoring but it lied. Over several thousand miles it calculated out as 47 mpg, 6 mpg than the car led me to believe.

Can you explain how?