Thank you for your advice.
Sounds like the 6" is the way to go then.
I am in Canberra and don't know of any decent stores here so have been looking online. The best price I have found is from Astronomy Alive who have the 6" for $329. It seems to have the same accessories wherever I look so unless there is an issue with service then price looks like being the deciding factor. Freight is pretty similar from any of the stores as well.
I don't know whether we will be taking it out in the car very much, Suzy, but I expect it will fit easily in the hatchback with the back seats down. Then hubby can drive the scope and I'll drive the kids. I think we'll be doing mostly backyard viewing though so not a big issue at this stage.
I'm glad to hear that you were so happy with your 6" dob. It's always good to get recommendations from personal experience.
Strangely enough I found a planisphere amongst our piles of junk when we cleared out a room a few weeks back. I love the idea of getting them started on that now.
I fully expect the rain.
It's pretty much inevitable. If you buy something for outdoor use the weather ALWAYS knows.