rover 220 diesel suspect turbo fault?

thanks to k and vince for their replys to the following question: my rover 220 diesel has always been quite quick but since a couple of days ago it has been very sluggish, I'm guessing it's a turbo fault, I'm competent with any kind of repairs but wondered if there are any sugestions as to where I should start investigating this fault, thanks for any advice any one may have. I have checked the hoses for damage and secure fitment, with the hoses off I checked that the turbo veins turn, also that the waste gate is free, I wondered if any electrical sensors could be at fault. thanks again if anyone can help with this one.