Keyplus,
Are you been serious ? or are you taking the p**s ? oh yes of course April fools day . oops no thats in a cple of weeks

Seriously, £30 to clean runs covered in lord knows what? you have already mentioned ink !!! dont know why ink from petals, but if you say so. you sure it is not perhaps pollen from the stamens, any way back to the price.
You are picking them up cleaning and returning , i would say thats £30 before you start depending how far, then you may have to spend half an hour on one ink stain alone , ink is a bugger for been never ending just one little speck can cover a towel, so i would suggest you you tell them the facts of how big a job it is, and quote at least £150. or walk away .