Hi all
Thank you very much for all your replies. For the EGR fault i replaced the vaccumn solenoid valve which cured that. Checked the air filter which was fine. Customer wanted an oil service doing which involved changing the crankcase breather located on top of the rocker cover. On removing the breather it looked very blocked and rock hard. After putting everything back together took for a road test and everything was fine. Spoke to the customer a few days later and he said no black smoke and was fine. Thanks to everyone for their inputs.

Regards Jamie