Dear Alister,
Thank you for your e-mail to the Advertising Standards Authority (ASA). There are not any mandatory labels for alcohol advertisements, but I would recommend you contact The Portman Group for recommendations beyond what the Codes stipulate.
You can find out more about The Portman group here: www.portmangroup.co.uk
Kind regards, Olivia
I followed their advice and checked out The Portman Group. They had a PDF of their guidelines as well as some 'Best Practice' guidelines that are not mandatory but promote a responsible view of alcohol. The PDF of their code is almost exactly the same as the CAP code, just slightly more brief. It is available here:
http://www.portmangroup.co.uk/assets/documents/4th%20Ed%20of%20Code.pdf
Something interesting I pulled from the Best Practice guidelines is the promotion of 'Drink Aware', which is a website that educates and promotes safety in the consumption of alcohol. Companies can (as an option) promote the drink aware website on their labels/marketing to show a responsible attitude to drinking. To show the logos and links in the marketing and on the labels it requires the company contain a free license to do so. As far as I am aware Magners does not have a license for drinkaware as it is not any of their labels or advertising but there is a link to it on their website, so I will not use this in my advertising but instead just use the self regulated 'Enjoy Magners Responsibly' message.
http://www.portmangroup.co.uk/?pid=28&level=3