Ocado CRM email almost works

Just received what I guess would be called a CRM email from Ocado.  They are offering me £5 off if I order over £75 worth of shopping for delivery tomorrow. Great in theory, but they clearly don't understand the nature of shoppers...
I haven't stopped using them because I have gone to Tesco.com, but simply because I like seeing stuff I buy before I buy.  So, I went to Waitrose at the weekend.  The CRM systems there obviously don't link up with Ocado, unlike Tesco's integrated system.
This means that whilst I like the idea of £5 off, I don't need £75 worth tomorrow.  They should allow a longer time window for this type of promotion...
Unlike many companies with which I deal, I am happy with the idea of a relationship with Waitrose/ Ocado but there is no way for me to reply to their automated email and let them know what I think of their offer!
Having said this - Ocado do have a fantastic level of integration between DM and email.