Is it allowed to for example when calling in to the radio on air, slip in your link. If you did it subtly where the show host asked you a question and you bought the attention to your website, would this be allowed, or would they just block it out?
I wouldn't be too concerned about the legallity of this. Many radio presenters name drop by 'mistake' often resulting in free goods being sent their way. The clever bit is how you drop the name in. Try to reference the site in conversation, alternatively a good way is to NOT mention the website name but to create curiosity. People by nature are inquisitive, circle round the product name for long enough someone will want to know what the product is.