Assume it is the Max Lambda. Just confirm they are using max allowed 1.05 as per Driver & Vehicle Standards Agency In service exhaust emission standards for road vehicles (eighteenth edition ?).
I have noted that most MOT stations use a max of 1.03 for my 4/4, but the above publication quotes 1.05, the same as the V8s.
If you note the same, you can download the publication from Gov Website. Sorry don't have the link, but that is where I got my copy. The copy always goes to the MOT station, just in case. On Monday my 4/4 passed but at 1.03, so OK.
Oh Lower is quoted as Min 0.9
