I used to door knock but you never know if the side gate is padlocked when you do that (obviously you can't try it before you knock). So I drop leaflets instead these days. On the back of the leaflet I have the following:-
r we acknowledge that a good, reliable customer
deserves a quality, reliable service. Some
customers have been with us since the early
1990s. Let our record speak for itself.
the cleaning would normally take place at
approximately six weekly intervals
there would need to be reasonable access
around the outside of the property without
needing to make an appointment
it is the customer’s responsibility to ensure that
payment is made within fourteen days of the
clean as we do not return to make doorstep
collections
in order to supply the service in a reliable
manner, it is sometimes necessary to clean in
inclement weather
we take our responsibilities seriously and
endeavour to work in a manner that is safe for
both ourselves, the customer, and the public.
We also carry a public liability insurance
policy in the unlikely event that a problem
occurs.
The "r"s are bullet points on the flyer but it hasn't translated very well onto here. Note the third item down regarding access.