I forgot to mention, larger tyres slightly change the gearing giving a small hit in acceleration and the ability to hold a gear on an incline. I've been out on runs with modified Disco's sporting 37" tyres which is around 6" over standard and they were crawling up even the smallest hills on the freeway drive to the tracks.
If you get those larger diameter tyres then your emphasis has to be 100% on off road ability.

Having re-read my post it could be interpreted that I may have been trying to draw parallels between the Impreza and the Freelander, this was not my intention!

The impreza suited a period in my life and I am now loving the more laid back style of the freelander.

The purpose of the comparision was an attempt to say, I had ruined a great handling car with a bad choice of tyre, at the time it was a switch from Vredstein to Uniroyal. The tyre size had remained the same and the Impreza was a standard car.

My concern is that I like how the freelander handles now, when I first started to drive it I think it was shod with Toyo Proxies which seemed to make the car jiggle and bounce on english b roads. The General Grabber that replaced those seemed to sort the ride out and make it more complient, I suppose softer which at the time I put down to side wall flex. So, an AT tyre I am now guessing it likely to be softer, this is perhaps not a bad thing.

appologies for grammer and prose, I am presently enjoying some rather nice Gin

Will 245 70 17 affect the traction control system adversely ? When I die, I want to go peacefully like my Grandfather did, in his sleep -- not screaming, like the passengers in his car

No. The bigger tyres affect the gearing and the real world speed of the car. The car computer will think the car is going slower because the wheels spin slower for the same speed. This will also trick the fuel consumption for the car as it thinks it has done less kilometres for a tank of fuel. For 245/70/17 you are looking at around 5% change, so when you travel 10,000kms real world you have only in fact wracked up around 9500kms on your odometer.