whats the difference between secondary banks, fringe banks and clearing banks?

Answer 1

Sounds like something you an look up yourself on wikipedia ..
... well what do you know ? wikipedia is so US centric it hasn't even got an article on Clearning Banks !

Clearing Banks (also used to be known as the 'big four') are the major Banks that process (daily) transactions amongst themselves on a 'difference' basis ...
.. for example, say one one day NatWest customes paid Barclay's customers a total of £10 million ,
and Barclay's customers paid NatWest customers a total of only £9 million,
then NatWest would send Barclay's the balance of £1 million ...