Had a look at Manby last year when viewing for poss venue for TBEC, it isn't really a MX course as such.. it has tracks, hills, some poss boggy bits, i think theres a few fields to cross and possibly a wood?! Looked good, but I would imagine it to be a tad slippy when wet

Surface is clay and expect a few puddles
Take your thermals...as the place is a bit exposed
Have a look at Banovallum MCC Enduro clubs pics, they have events there
http://www.dephotos.co.uk/emAlbum/cgi-bin/pro/emAlbum.cgi?c=show_album;p=Motorsport/Manby%20MotorPlex/2006/Banovallum%20MCC%20Enduro%2029th%20October