With regard to viability:

There are a number of launderettes 'locally' which certainly have had more
money spent on the outside than the one at Forest Hill and which do not
seem to be under threat. (Brockley Rise & Perry Hill spring to mind). They
do all however stick to the core business of old fashioned laundry. The
Forest Hill location has a good opportunity to extend the business and, I
suspect become quite profitable (though I suspect less so than starting an estate agent).

If the launderette was mine, I would make the most of the increase in young (and old) affluent office-workers who have moved to Forest Hill in recent years, whilst
retaining the core current clientele.

1)  I would offer ironing services and advertise especially to office
workers that they could drop off their shirts in the morning and collect
after work in the evening. I know there is demand for this amongst young
professionals and currently see people take their laundry into my office in
Canary Wharf where there is a laundry service. 'My Beautiful Launderette'
would compete directly with this and I would expect it to win on cost and
convenience.

2)  I would extend and advertise my Service Wash offering. Personally, when
I lived in a flat, I took my sheets and towels to the launderette at the
end of my road. I don't understand why more people don't do this. A large
wash could do all my linen in one go, whilst in the flat, it would take a
full day of loading, draping (creating tent structures around the flat) and
folding on my own (getting wrapped in sheets). I considered this a total waste of a Saturday.

In order to bring in the above clients, I would refit 'My Beautiful
Launderette' both inside and out, making it a nicer environment for current
clients and staff, as well as a strong visual presence on the Forest Hill
High Street.

All the above has been tried and tested in other parts of London.

In addition, 'My Beautiful Launderette' would offset the cost of staffing
for longer hours with additional features:

3)  'MBL Socials': After say 6pm at night, I would look to create some
social nights. So far on the calendar are: a) Book Club - I always read at
the launderette - seems a natural fit (I might extend to chess & mahjong
nights) b) Singles night - a launderette seems a nice, safe environment to
meet people who are likely to be local to the area. I would look into
licensing and may try wine & beer sales on these nights. Certainly teas,
coffees and soft drinks would be available.

Sadly, I do not have the funding or the time to make this reality, but
maybe there is someone out there who could.

I am tempted.

Crowd funding?