When these guidelines were drawn up by the Department of Health many years ago, a typical glass of wine was considered to be 100ml at 10% alcohol by volume. Nowadays, the quantity in a wine served by the glass must be 125ml, 175ml or 250ml,  or multiple thereof, under the Weights and Measures regulations. 125ml is considered too paltry, so one has a choice of a "standard" glass - 175ml or "large" glass - 250ml (a THIRD of a bottle). Coupled with this,  a typical glass of Aussie or Chilean wine is likely to be 14% abv or more.