Martin,
Wer ein north warwickshire and 2 years ago we went from 5 pass system (subsoil if required, plough, roll, power harrow, drill, roll), to a 2 pass system. We tested various cultivation methods but because of our soil type and soil grade a direct drill was not considered. So we went down the middle with a cultivation pass (non inversion) and then a cultivator drill. The machines we use are a 3metre Simba Solo and double press and then a vaderstad drill. Were now establishing our crop for about £22/acre all in. If the weeds chit suffciently with the stale seedbed we spray off as well which puts the cost to about £25/acre.
The old system cost us double that if everything went ok. sometimes an extra powe rharrow pass was required etc. Yon might say that was a big investment. well it was but we needed a new tractor and plough anyway, a new drill and a new power harrow. Add it all up and the cost is very similar. We were able to shed a staff member as well thus saving even more.
The cultivator running costs are less then a pound per acre. the crawler, driver, fuel and finance however put the cost up to about £12/acre. We foresee the machines still here in 10 years time as both simba and the crawler are excellently built. I am keen to try other drilling methods in 2003 and i think the hosrch or new simba freeflow drill will win. The next step for us like you is the combine with a full spread chaff spreader as this can be a problem with min till systems