Lambeth

Lambehythe

Malory mentions Lambeth:

Then Sir Launcelot... took the water at Westminster Bridge, and made his horse to swim over Thames unto Lambeth.

I do not know whether in this context Lambeth is a castle, a religious center, or simply a place name for undeveloped real estate.

Lambeth is a district in London, and the name is recorded as Lambehitha ('landing place for lambs') in 1062; and as Lambeth in 1255.