The Peregrine certainly is indigenous to the Norfolk Broads. The UK population were hit hard , along with may birds and mammals at the top of the food chain by the use of DDT. When it was banned in the 60s they slowly recovered.
http://www.rspb.org.uk/discoverandenjoynature/discoverandlearn/birdguide/name/p/peregrine/population.aspx
Their 'normal' habitat is rocky cliff faces. There being a shortage of such in Norfolk they have, as elsewhere adopted tall buildings. Locally,as well as the Anglican Cathedral there are nesting pairs in Kings Lynn, The Cantly Sugar works and St Nicholas Minster in Gt Yarmouth and a number of other sites. Their favorite prey is the feral pigeon, of which Norwich has a large population ! Whether our fine city is a suitable habitat for them,, well, I think the birds have decided that for themselves.
http://www.rspb.org.uk/discoverandenjoynature/discoverandlearn/birdguide/name/p/peregrine/habitat_food.aspx
The Peregrine Falcon is one of the World's most widely distributed species, in fact the only continent where hey are not resident and breeding is the Antarctic.
The peregrine is afforded the highest degree of legal protection under Schedule 1 of the Wildlife and Countryside Act 1981as is the Bittern.
Should a young bittern be preyed by a Peregrine, that as they say is 'nature, red in tooth and claw'.