"We can apply to court for a search warrant to gain access to your property" - you can't get much more intimidating than this can you?
"An Officer may interview you under caution" they are salespeople NOT POLICE!
"Anything you say to the Officer may be used as evidence in court" - just say No Thanks and close the door.
"If your property needs a TV Licence, you will still need to buy one" - no shit Sherlock! If you watch Live TV (of any kind) or use the BBC iPlayer then you need a TV License, if you do neither of these things then YOU DO NOT NEED A TV LICENCE!
"In Scotland, Scottish criminal law applies" - you don't say! You've sent me the letter yet you aren't sure if I'm in Scotland or not??
"A reminder of the law"
"Let us know you dont need one"
This is a complete and utter LIE, there is no law that says you have to do this. If you do not need a TV Licence then do not buy one, that's all you need to do.