Thanks for your help guys,
Decided to change the oil and filter first thing, the oil was no problem used a BP turbo diesel engine oil 15/40 viscosity.
The filter though thats another story, could not get it off, in the end I had to remove the whole casting from the block and get it off in a vice with stillsons!!
It was worth it though as the oil pressure when warm is around the 4 bar mark but still nearly 5 bar when cold, but I can live with that.
When I eventually got on the water and opened her out the revs top out at 2100 which was about 26kts with 2 pob, but no excess smoke so I will probably check throttle positions, fuel pump settings before anything else.
On my return another problem developed! The stern drive wouldnt trim all the way up? On looking at the pump I discovered the motor and reservoir had almost detached itself from the pump body and lost all its fluid into my newly cleaned bilge in the process! (I had spent hours cleaning them after I managed to get hydraulic oil everwhere when overhauling one of the rams)
So I have spent the rest of the Afternoon removing/repairing and replacing the trim pump.
I hope not all my trips to sea are this involved but I suppose its better to get these problems out of the way before summer