Front radar Pulsar 2015

I am a newbie and looking for some advise NOT from my Nissan dealer :) I bought my Pulsar 7 weeks ago, 64 plate Tekna.  After driving off the forecourt and around for a few miles a warning came up on dash about the front radar.  The light on the speedo looks like 2 car bonnets/fronts and a star in the middle.  I was moving house this day/weekend and thought its not red so I leave it look at manual and call Nissan later in the week.  Called them a week later and not had a stop/start fault and front radar obstructed warning and a key fault.  Called Nissan and arranged a week later (so 3 weeks in) for them to change the battery on the car to see if this helps.  It did for about 5 minutes and again all these warning came up.  Booked it in another 2 weeks later with another branch who advised there was damage to the vehicle causing issues with the front radar thus causing all these other issues and they couldn't repaid it under warranty as damage is not covered.  Spoke again to where I bought it from and they booked it in last Saturday and have had the car all week.  They are saying it looks like the car has hit a bird or animal on the from grill thus causing damage to the front and stopping the radar working and it would cost £1600 to repair.  Now i have argued until i am blue in the face saying it was like it when I bought it and I did not notice this damage to the vehicle.  They also say they done a 84 point check and this fault did not come up.  If i knew I was going to have a fight on my hands I would have returned the car within my 30 days and cancelled the order.

My question for you guys n gals is, does the computer in the car not log a date and error code as to when this issue first started?  Can i not prove that it was like this when I bought the car via the computer?  I am so frustrated, who whole buying this car was a pain from the start, it took them 4 weeks to get the car sorted for me to collect and now this!  When I picked the car up it was all sparkling and like new, i did not crawl around on my hands and knees to see if there was damage(that is visible) to the car.  I found all other dents and scratches on the car which they rectified) but not this damage on the front grill.

Can anyone help with the computer question?

thanks very much and by the way I still love the car so I still want to keep it :)

Clare