Cats when moving house??

[fairimum]

We are moving house, but only about 1 1/2 away by road - the problem is the new house will back onto the same fields as our current house (houses only apart by mayb 1/2 a mile across the fields) - am really worried about getting our new cats to stay in the new house and not come back here (currently come in and out of the window so could well do that with new owners if the window is open) - any ideas greatly appreciated... we were planning on keeping them in for 6 weeks (will be hard enough for our boy as he is a very out doors cat) but should we consider longer? giving them yummy wet food (only have biscuits!) to show should come back to new house??
help!!

I would have thought that 6 weeks was too long.

We only kept them in for a week or so and they were fine.

even so close to the old house?
Just our boy cat is always out in the fields and goes quite a long way - easily as far as the new house!

I think a couple of weeks of keeping them in is enough. On their first day keep them in one room with food, water and litter to help them settle until they feel ready to explore rest of the house without scrambling up curtains, chimneys, getting stuck behind kitchen units etc etc.