Challenge Grifo Pro 32, wire bead.
Yes wire bead, sounds heavy but actually the tread is taller than most of that pattern (inc the folding version!) and the stiffer sidewalls mean you can run lower pressure and get more consistent cornering at low pressure. I got these on suggestion of more experienced cross-ers and have been pleasantly surprised.
Earlier this year i bought a Clement MXP and was quite disappointed coming from my old worn Mud2s, happer now ive got a grifo on. I think a new Mud2 would beat a grifo for heavy wet conditions, but they are quite a bit slower rolling.
Grifo wire are £15.50 each (tho are now black-wall not tan-wall, as shown here)