When I put in for large commercials, I get two references as standard, as follows
Reference
Customer Details
name
address
town
postcode
Summary of account
We have provided our services to the customer stated above from (date) and currently do so on a (weeks) weekly basis. Our services include the cleaning of ...
Statement of reference
I confirm that the details stated in both the customer details and summary of account section above is correct, and would recommend the services provided by (company name).
Referee Details
Name: _________________________
Title: _________________________
Signature: _________________________
Date: ___/___/2009
____________________________________________________________
however with small jobs I just say I do a few of your neighbours, would you like your window cleaned?