I have been speaking to a FL driver based at Peterborough and have been told you predominantly do HH with some IM thrown in, the routes can be;
go as far north as toten past Leicester, but can go further depending on requirements, Peterborough to Ely Peterborough to king cross Ely to Liverpool Street Ely to Ipswich Ely to Norwich Ely to kings cross Liverpool Street main line to Ipswich and Norwich North London lines South Tottenham lines Midland main line Then lots and lots of loops and junctions across the routes and diversions like Hertford loop and seven sisters loop, and branch lines like Felixstowe ect and being based at PBO you only sign class 66's
Hope this helps