Fishtank I think your find they make real savings. In terms of Gatwick they have managed to remove one imp by get the other imps to work faster and adapting it to suit their needs. The imp then gets put into another mail centre saving them buying another one and then the best praticse is then rolled out to other world class sites.
In addition they review all the accidents and find the root cause and then find solutions they have reduced the number of accidents by 3/4 therefore saving them money on time off , and compehsation from legal and medical claims.
They also anaylised how far people were trunking the DSA yorks to be tipped and then processed , they believed 30 percent of time was trunking to the tipping tables and therefore moved the DSA holding unit right next to the tipping table and therefore removing all that trunking time and the net result two duties lost.
Other examples are where the imps tear letters video the machines to find the faults and then adept the machines and then save the compensation they have to pay for the tearing of letters , plus they save on breakdowns as the machines processes more and they save on engineering costs.
There are countless other costs they believe they are saving.
So I would suggust that they do believe they are making real savings. Now I agree will they make the savings in a delivery unit especially as most accidents are on delivery and when an indivdual on their own. The two trial offices for deliveries are Taunton and Burguss Hill. No other delivery office can have world class mail until their mail centre gets 20 points in an audit. So I would agree the jury is still out on WCM in delivery units but in mail centres it is something we need to recognise as something which Royal Mail believe will ensure they save money in the future.