Megan - I suspect it's the same agency because they also told me the same thing. I asked the council and it's nonsense - legally the landlord is not able to give permission for it to stay up past 14 days.

The council enforcement team intervened and hey presto, the board has vanished. They were really helpful - give them a call if the agency still refuse:

Jody Solomons
Planning Enforcement Officer
0208 314 8092
Jody.Solomons@lewisham.gov.uk