Requirements for an RWC include no oil leaks and working seatbelts (which includes retracting properly).
While an RWC requires all external lights to be working, I don't think it covers internal lights.
The problem you have is that you noticed this after driving for two weeks, which means that the dealer will likely claim that the problems weren't there when the RWC was issued.
If it came with a warranty, then that would be the way to pursue it. Otherwise, you can try to push it as a roadworthy issue, but there's no guarantee you will get anywhere.
Here's some personal experience that may or may not be of help in the future...
$22,000 is far more than I would ever pay for a 7 year old car with 250,000+kms on the clock. If you're willing to buy second hand without warranty, you will always find much better deals at auctions ("real" auctions, not eBay). Ex-government cars often go at a slightly higher price, but are usually the best value for money. They usually come with the original owner's manual and service history - and the owner details in the manual will often indicate which department or agency the car came from. You can use that info along with the service history to help decide whether or not you want to bid on it. Best of all - no salesman feeding you BS about the vehicle's history or condition.
The last one I bought was an 8yo Futura wagon with 214,000kms - original owner was Broken Hill Council and I paid $4,000 for it. I've had it for years now and it's the most reliable car I've ever owned.
(In years gone by, I would have recommended avoiding ex-police cars - they often have lower kms, but they're "hard" kms if you know what I mean. But that doesn't seem to be as much of an issue these days, so it basically comes down to personal preference.)