The lettering is from a social grading system commonly used in the media in the UK for advertising and demographic classification purposes (based on job category)- the class system is unofficially alive and well in Britain. It's not quite 'Downton Abbey' but it's one of those behind-the-scenes things that generally no-one from outside the UK ever truly understands, yet everyone in Britain instinctively gets it.
A - upper middle (CEOs, solicitors, doctors etc.)
B - middle (senior managers)
C1 - lower middle (junior managers, office workers)
C2 - skilled working (plumbers, electricians)
D - non-skilled working (labourers, retail workers)
E - non-working (benefits claimants)
Broadly speaking, A-C1 are 'middle class' and C2-E are 'working class'.
Interestingly, outside of London I'd actually say the majority of Britons drink instant coffee, we don't really share the cafe culture found in Europe or the US.