[Js116i]

Hi all!
Sorry i know this has been covered many times before but I'm failing to get to the bottom of it. I have read every post relating to misfires.
My 2014 n13 116i with 38k miles has a misfire but if driven gently shows no fault codes. These only appear after giving it a fair bit of throttle making the car misfire and shake badly then the drivetrain fault appears along with all the fault codes most of which relating to cylinder 4.
The car had been parked up and left for 4 years before I bought it with a suspected timing chain issue even though it sounded fine - I had this changed anyway when I bought it.

Fault codes were
140010
140410
140001
140401 (all of these were relating to misfire cyl 4)

801C20 - ZGM central memory full - no control - unit fault

Its just had new battery, ngk iridium spark plugs, knock sensor, full service, timing chain and 4 'used' injectors.

The fault codes were mostly relating to cylinder number 4 misfire but when i swapped plugs and coil packs around the fault didn't follow to a different cylinder.
The garage had the car to do a compression test and since having it back it now says cylinder number 1 misfire instead of 4.
They have suggested replace all coil packs with quality bosch items and getting 4 bosch spark plugs to match.

I'm hesitant to do this though as when the plugs and coils are moved around the fault doesn't move. How it has moved from 4 to 1 since they have done compression test has baffled me.

Anyone have any ideas please? I'm at my wits end and don't want to throw money blindly at it.
Thank you