This is the e-mail I sent:
Dear Sirs
On three occasions recently I have visited your store in the Arcade, Broadmead, Bristol.
On the first occasion I noticed that the toilet was generally not very clean and the toilet pan was stained and dirty. This was the upstairs toilet.
On the second and third occasions I used the downstairs toilet, which was a lot cleaner, however, on the second occasion I noticed a toilet brush in the corner which was dirty (I'm sure I don't need to describe what I mean).
On the third occasion, in addition to the dirty toilet brush still being there, there was no toilet roll and the receptacles for sanitary products had obviously not been emptied, and in fact there was a blood-soiled panty liner at the side of the toilet.
I do not know if this is representative of your cleanliness in the rest of your stores - I certainly hope not, as I feel most disinclined to go back to this particular store or Starbucks in general.
I am not the kind of person who generally writes letters of complaints, so I hope you will take this matter seriously. I am sure toilet hygiene is very important in a place which sells food and drink.
Yours faithfully