I'm not a teacher so not really the best person to help here, but there are some others around who will be able to help. There is quite a bit of advice for each of the subjects here: http://www.elevenplusexams.co.uk/advice/
(look down left hand side) - there are quite a few resources mentioned there. If you can get some old papers it will give you some idea of what they are testing.
Just to complete the picture re the schools, there aren't any big indie preps in the area preparing for Ratcliffe -there are either v small indies or those attached to senior schools (eg elms @ trent, fairfield and convent @ loughborough).
Most of the local kids who go to Ratcliffe in year 7 will have been at Ratcliffe prep (not all stay), Grace Dieu school (although most of them stay at GD until aged 13 then move on) some other local independents and I suspect many from the local state schools who will have been doing the SATS etc.