Fabia VRS Fuel consumption high (UPDATE)

I believe that I have found what could have been causing my high fuel consumption on my Fabia vRS. From my previous thread I was only managing 47mpg on my daily commute of 100 miles. Having seen afew threads on EGR cleaning, I decided to give it a go. Whilst in the process in removing the elbow pipe from the intercooler to the EGR valve I noticed that the pipe was not quite flush with the EGR valve assembly. It became obvious that the two lugs which locate in a slot secured by a clip was not fully located. It was being held by one lug and the other was just off. Having properly located the two lugs, the fuel economy has improved to about 55mpg (more respectable). I am not sure as to whether this is the sole cause but it has made a difference. I have previously experienced the pipes coming apart near the upper pully assembley, which results in a lot of black smoke and no power what so ever. This has often been mistaken by turbo failure (thank god not). I will get round to cleaning the EGR valve. Has anyone experience any major change after cleaning it??