Thanks for the replies. There was no oil in the intake system from previous failure. Just in the exhaust system which we cleaned out. The turbo was a new unit bought from local factors from a company called BTN. We have just checked the return pipe for blockages and removed the sump to check oil strainer and they are ok. Oil pressure is in spec and no blockages to oil feed pipe. Bit stumped really! Thinking it must have been a faulty turbo (turbine shaft has broken again) just wanted to be sure before we throw another turbo at it. Just what we need before Christmas!