[aeshna5]

I live in south-east, so don't know NW that well, but over years have visited Leighton Moss good for Bittern, Marsh Harrier + whole array of waterbirds, Martin Mere WWT for wildfowl particularly Pinkfeet, wild swans + Morcambe Bay is one of country's top wader sites. There's a series of Where to Watch Birds guides so have a look at the one covering your area + that will introduce you to other less well known sites.

Also ask your local RSPB or natural history society for good local sites + perhaps join them on outings if you're an inexperienced birdwatcher.