On page 28, Table D.1 specifies minimum illuminance for specific locations. Now as we all know, british Standards are published in many shades of grey, and are open to interpretation, and also misinterpretation.
Here is an example. Page 26 of the standard defines examination and treatment rooms as follows: -
The illumination needs to be sufficient to enable complex procedures to be completed, e.g. minor operations.
NOTE Operating theatres are outside the scope of this standard.
Would you consider a dental surgery where a patient may be undergoing root canal treatment, to be a treatment room? If so, they now require a minimum illuminance of 50 lx within 0.5 seconds, horizontally on the working plane. Im my opinion, 50 lx is a lot, it's probably more than they would have under normal lighting conditions.
I also wonder if it could be an error on the table.