There is a planning application to put a mobile phone mast at the top of Dog Kennel Hill. Residents of Camberwell Grove and their friends in the Camberwell Society are fighting it - defacing their nice conservation area with ugly laminated posters! They do not benefit from it as reception is fine on their side of the hill.
https://planning.southwark.gov.uk/online-applications/applicationDetails.do?activeTab=makeComment&keyVal=S9IKT2KBN1200
I do not think there are any health hazards from being near phone masts (or at least they are negligible relative to everyday risks we all face). Anyway, here is what the NHS has to say about them:
https://111.wales.nhs.uk/encyclopaedia/m/article/mobilephonesafety/#Risks
I imagine this will spark some lively debate!