traffic dci 100 55 plate ,lack of power?

Hi the van has done 180000 miles bought it cheap had it six months ran sweet . went out other day got set of lights wont rev above 2700 seems like its missing changed air filter fuel filter tried again come to a hill glow plug light comes on . took it to auto electrician said it was egr valve he changed that no change . plugged back in no fault came back to me only thing he could think of tubo knackered took it to diesel specialist plugged it in no faults think its turbo want £1600 anybody any ideas ps van starts perfect every time cheers stuart p---ed off trarric owner