I think i've been a right old doofus...
I checked the oil this morning, on level ground, cold engine. Dipstick showed oil level at about a 1/3 over min. Last time i checked a few months ago it was 1/2 so i thought i had better top it up. I topped it up with 250 ml then drove it 80 miles (no thrashing, very rarely hit 3k rpm in 3rd gear or above and never went near 4k). I let the engine cool and now the dipstick is reading that the whole of max is covered
.
Am i within a tolerance that won't lead to frothing or Cat damage or have i been a proper dipstick and do i need to get some drained? (i'm guessing this could be likely as Max should mean Max).
Just to repeat - oil level was a 3rd on the dipstick and i put in 250ml - I guess i only needed to put in 100ml or less but should have done so in very small increments and kept checking the dipstick...