I've finally convinced someone to get broadband and thinking yay I get another 25p off. But find that if you go via Broadband Choices they are offering new customer 4 months free. Is there a way I can get my referral and also get the BBChoices deal in one or do we all loose our ability to get referrals while that offer is in place. Seem mutually exclusive? I might keep my mouth shut! 

Unfortunately not. You can only take advantage of one campaign. If your referral signs up using one of the affilliate schemes then the referral payments would cancel out.