Here goes: -

Excerpt from LUL Referance Manual:

"SECURITY ON STATIONS

Standard Sa109

10. Photography on stations

10.1 Passengers can take photographs with small cameras for private
purposes, provided

* flashlights and/or tripods are not used
* no obstruction or inconvenience is caused to staff and/or passengers"

10.2 Representatives of the media, press or photographic agencies and
film companies, and other persons taking photographs for commercial
purposes must first get permission from the Press Officer. See section
13 of the document."

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No doubt they can still ban you under the "inconvenience" clause but
they'll somewhat shoot themselves in the foot if they first quote a
non-existent total ban, them move the goalposts when proved wrong!