London to Cornwall - where to stop for 2 yr old

[negrilbaby]

We're off to Cornwall in October and I'm dreading the journey. DS is 2.6 yrs and DD will be 3 months. Can anyone recommend places to stop en route? We're happy to make an extended stop if we can find somewhere of interest.

For a good run round, Cribbs Causeway is good - they have a small softplay area, and a good choice of places to eat

STonehenge- they can run around for a bit and burn off some steam.

Thanks for these.