Great to see some enthusiasm and interest in this idea!
As a suggestion, it might be better for someone with some design experience to design a simple website and a simple logo for the sticker.. first stage would be to register a catchy domain name like stopandcharge.net / stopandcharge.org.uk, cyclecharge.net / cyclecharge.org.uk. Perhaps someone else can come up with a better name?
Getting the type of vinyl stickers printed that go in windows wouldn't be too expensive, I've dealt with printers in the past and probably looking at less than £200 for a decent quantity of a 500 or so.
What might be an idea is, we form a team of volunteers to operate the site and roll out the scheme, but seek to get it funded by the ebike industry.. we could approach each manufacturer and ask them to donate a small amount to get it started...whatever seems reasonable, £50-£100? In return, we'll allow them each to be listed on the website as sponsors with a small ad and link to their website? Another possible revenue source might be some kind of government grant as it's certainly promoting their greener economy policy while helping a new industry (ebikes) and also small businesses and their communities.
The website itself could be kept very simple just a couple of pages, one to explain what the scheme is about and how it works, how much charging batteries cost etc.. and then we could use some freeware directory software to list all the establishments which have joined the scheme.. You can browse by county/town or search. A website modeled on cycle-route.com might work well?
Businesses could either sign up online themselves, or bike owners could leaflet them/go in in their locality and ask if you want to join and give them the url? Each business could be allowed to enter some details of what they do/sell and upload a photo and directions maybe, or we could find a way to link google maps or cyclestreets.net.. It would be open to any kind of establishment, from a pub/guest-house, to a corner shop or even dentists etc? Our aim would be to build a nationwide network of charge points to extend the range ebikers can travel ultimately. We could even have "emergency" charge points which are private houses, if other ebike owners are willing? These wouldn't have stickers or be advertised, but be could be found on the website and identified as private residential areas? Just have some general rules about using these places, like phone/email first, don't turn up unannounced or late at night etc.
I don't know if it would be worth establishing a charging fee but I think it might be unreasonable to expect some people to use their facilities without paying in some cases? How about, if it's a guesthouse/pub or whatever, if you use the facilities the charging is free. But if it's a place you aren't going to provide any custom, you pay a small fee, i.e. £1 - £1.50 an hour? We could set the rate on our website nationally which all members agree to? At least such a small charge would protect establishments in busy areas from a big electric bill if several people a day were charging (unlikely) plus it would help cover wear and tear etc. If we don't establish a fee system from the start, we could certainly leave it open for future as more people get ebikes, so members don't feel it might become a financial burden and be put off joining?
To start the ball rolling I don't mind registering the domain and doing the website if nobody else fancies it..I do have experience as a web developer and have my own hosting facilities and business contacts.