Hello to one and all

[hellhawk]

first off i want to say this is a great site as i do all the work on my cars.
so heres my story ( it my get to be a war and peace)
I bought my R reg 1998 lwb terrano Tdi se touring with 120000 miles from a dealer in manchester, he said it had been looked after very well. When i looked at the terrano it looked great blue over silver just the colour i (my wife) wanted manual leather, 7 seats. took it for a test drive it was great.
So i bought it for a good price. and drove it back home to Kendal where i live. Next day a trip to auto parts in kendal (best place for oil filter and parts etc.) got oil filters and new drop down links and water pump and it leaked water everywhere.
i stripped the inter cooler off with the air filter and the breather. this is where i started to worry, the old air filter had been marked with the last service milage of 98000 miles. the turbo had oil in it and the intercooler was full of oil also the outside of the turbo was covered in oil.
so two cans of carb cleaner later and all looks good.
The week after we go on holiday to our house in france (Dordogne) 14 hours of driving. the terrano never missed a beat all the way down. it sat at 80 mph with a 500 liter roof box on.
when we get there i did a little calculation of fuel and found it to be doing 21 mpg not good, also there was no oil when i checked the dip stick the following morning. so i buy oil and fill it up.
So we drive around france for two weeks and it starts doing 28mpg!
again when we drive home 21mpg and i keep putting oil in every few hours.
When we got home i investigate first the fuel. i remove the intercooler and what do you know its full of oil. when i checked the diesel return lines under the insulation covering them i find they are soaking in diesel, so a meter of fuel line and half an hours work and they are replaced.
As for the oil it turns out to be a breather problem the oil is being sucked through the breather and into the turbo, it then seep out of the rubber pipes that connect the intercooler to the turbo/engine and runs down turbo. Has anybody had this problem before and what is the solution please? would fitting a K&N filter help as in reduce the suction on the breather? the breather is clean and free from blockage.
Thanks in advance.