N16 cuts out and rough idles

Hi. I took my (2010, n16) mini one to a mini specialist garage to fault find and they said they couldn’t find the issue.
The car starts, then idles rough, misfires, sounds like the engine is surging as the revs are all over the place. If you Rev, it tends to get a little better but still not a smooth idle. When you start driving, you last about 5 minutes before the engine will cut out when you have put the clutch down and stopped. I have no idea how to fix this if even the specialists don’t know what’s wrong with it.
I have already replaced the camshaft sensors, vanos solenoids (although I used vanos solenoids from neo-bro’s and not from mini, could this be an issue?? ). There are fault codes relating to bank 1 camshaft over-retarded etc.. a whole bunch of codes.
One thing the garage suggested it might be is the oil pressure. So I have ordered an oil pressure sensor and will swap that in along with an oil change and filter.
Any advice gratefully received, thank you.