Thanks for the advice and tips everyone, keep them coming!

Feeling more reassured but must admit i am a bit scared about the trip, firstly for the long car trip and also because ds doesn't sleep very well outside of his own cot. Had a horrendous night in a hotel once and since then we haven't taken him anywhere overnight. We really need to do the trip in 1 day due to time constraints and also finances but will stop if it gets too hard. It isn't really a holiday, we are going for a graduation ceremony so dont want to spend too much as we are planning a family holiday in January.