Partner oil overfill

[mangifee]

Hi members!

I have a 53 partner, runs great no trouble never let me down, today i was about to travel a round trip of 380,iles so asked my yard lad to check the oil for me, he said he had done it and topped it up,

Off i went and 2 miles down the road there was a weird jerking feeling and unless i pressed the accelerator the van wanted to stop, i got to a petrol station and noticed a great deal of smoke and the engine ddint immediately stop when i shut off the ignition

after a quick tow home, i asked my yard lad how much oil he put in he said about a litre and half!?!

I retried the van and she startedlike a dream and ticked over for 10 minutes quite happily, so i took the notion to drive around the block for a couple of miles and see what gives, after about a mile and half she started the shuddering and smoking, it was almost as though the clutch was slipping, as the engine noise got louder and then dropped again with lots of smoke, this took about 30 seconds, i decided to head back home and took the back roads, there was no more smoke for about a mile then it repeated the action of a quick shuddering then was normal again,

Anyone please let me have some suggestions, or possible damage that may have been caused
cheers