If you are involved in an accident do not discuss who was to blame as this could lead to complications for you and your insurance company. However you should still take down the facts of what occured.
Making a claim will not automatically lose all your no claims bonus. Most insurers will relegate you only two years meaning if you had 5 years no claims then you would still have 3 years.
If you were buying a new car you wouldn't buy the first car you see. Car insurance is no different you can save hundreds of pounds by shopping around.