Cost would depend on the specification you want, ie how luxurious its going to get, as a rough guide, say £2000 per sq metre.
Now it depends if you are going to get one of these timber framing companies to do the deisgn work for the actual oak frame, but if not, factor in architects fees, structural engineer fees, M&E design fees, planning and building control fees, any costs associated with electrical, gas, water, sewage and BT connections to a new build.
Depending on the deisgn, and any planning requirements, you may be paying more for things like handmade clay roof tiles or reclaimed bricks.
That sounds very pessimistic, but plan for the worst and you'll not be left with an unfinished house.
If you need an architect and are near to North Yorks....ahem...