One stop breast clinic - they do all the tests there?

I received my appointment last week for the breast clinic. Before I did, a couple of days before I called the doctors surgery and asked the receptionist what sort of referral I had as I was unsure on wait times. The receptionist told me it was an urgent referral to the one stop breast clinic. On my understanding this is a breast clinic where they do appropriate testing all in one day if necessary right? My only worry is, my appointment is at 6.30 pm, isn't this quite late to be pulling out loads of testing? On my Letter it just states which consultant I am seeing. Nothing about tests or how long approximately I will be there. Just seems very late in the day even just to see a consultant. And experiences or anyone else had something similar. Thankyou x