compression on TD5

[bushmaster]

good day to all of you;

I just did a compression test on my Defender TD5 at the land rover dealer and of course they send me the results for 4 cylinders only.
I have the following results:
cylinder #1 : 28 bars
cylinder #2 : 27 bars
Cylinder #3 : 28 bars
Cylinder #4 : 25 bars
the comments from the workshop are oil emission on the cylinder #1

can you guys help me to draw the right conclusions from this:
If oil emission are identified it could either come from a piston ring or a valve. If the compression is high it should be a valve issue . Right or wrong?

what is the normal compression ratio on a TD5 ? I have been looking on the web but could not find any answer.

can you make comments on such results and recommend some course of action..

I am looking forward for your answers

all the best to everybody