Hi Matsfets,
First of all, take some deep breaths!
Going to court in your case probably won't be as traumatic as you're currently thinking - after all, from what you've said (i may have read the original post you refer to/ if indeed there was on here on UKY) it really does sound as though the other guy is just trying it on by contesting it. When it comes to court, by you explaining what you know, should show that it was his fault and not yours. However, as I or anyone here doesn't know the case it 'could' go the other way..
A few pointers I've been told from all my legal beagle mates
1. dress well for the court appearance - i.e don't go casual, don't look scruffy.
2. Wear a pair of glasses - even if they're plain lenses! - this one came from a good barrister mate of mine when i was 'potentially' going into court! apparently, it makes you look more intelligent!
3. Always be respectful in the courtroom and don't be afraid to ask for the question to be said again or that you need some time to remember the details etc before answering.
4. To help you in court, speak and be in close contact with your lawyer, and do as much background eveidence collection as possible before hand. Advice has already been given, speak to the insurance company and their legal dept. etc.
5. it also sounds as though his lawyer is trying to use technicalities to lay the blame on you - these things do happen as part of the whole 'legal' process.
6. I'd have doubted the fact your an expat should play much bearing, aside that 'they' might claim you are new to the UK and therefore inexperienced etc etc. I'd say don't be afraid to point out your previous exemplary history in the US and that you have and are more cautious here as you build up experience etc.
Some more advice may follow from others, but overall, i'd say not to worry too much, even 'if' it's decided against you, I'm assuming you have comprehensive insurance, it'll go down as a claim against you at most and an increase (possibly) on your premium.
good luck with it all though !
cheers! DtM! West London & Slough UK!