The most likely blockage risk is in the turbo feed pipe, you ought to have a go at this whilst your at it, cat will be in the way for,that.
Hi guys quick update removed the sump yesterday, managed to leave the exhaust in place just disconnected the joint. Hardest part was breaking the sealant bond to get the sump off I used a putty knife, man that original sealant was strong! Well back to the point I didn't even have to clean anything the sump the oil pick up, and bottom of the engine was as clean as a whistle to my surprise no black sludge in sight.
I remember reading on here about people saying about oil being left in the sump from the recess in the sump plug, and yes there is a fair amount of oil you will never get out from just dropping the oil!