Yes, 1.65mm too big.
(Engineering clearances notwithstanding!)
But looking at the photo again, I reckon you have a compression fitting on the greaser designed for 5/16" pipe and the pipe you actually have is 1/4", which is why it fell out in the first place. The 1/4" olive would have been able to squeeze through the 5/16" hole in the nut.
You need someone to actually measure the pipe and the fitting to determine the sizes. Then once known, decide on a sound method of connecting it all up.
I was in Banbury this afternoon and was about to set off down the M40 home when I asked where you are, just on the off chance you were nearby or en-route.