Hi, we've been using ACSI now for several years and have stayed at some great sites at fantastic prices, saving us hundreds of pounds. The only thing I'm never too sure about is booking in advance. For those of you who use ACSI do you book in advance and still get the full ACSI discount? I normally ring up the day before to check if there's room and then just turn up. However, I'd rather book in advance if I can still get the discount.