Entertaining discussion about spellings, maiden names and whether or not it was proven the snail was actually in the bottle in the comments section.
And yes, 'ginger' in Scotland is generally meaning any fizzy drink, not specifically ginger beer, but in this case, it was referred to specifically as 'ginger beer', so ginger beer it is! I imagine in some parts of England the case could have been about 'pop' :-)
T'was to be mixed with the ice cream they bought to create an iced drink, as reported in 1932 SLT 317.
Although personally, I prefer lemonade and vanilla ice cream for an ice cream float.
And no snail included, ta!