Exceptionally quick appointment for PIP assessment

This morning had a telephone call from IAS to make an appointment for my wife to have her assessment. They offered me a choice of venues near me all with an 0830 hrs appointment times. So now have an appointment for Thu 26th April at a centre of my choice. Only submitted forms which were received by DWP on the afternoon of 16th April, so they have been very quick getting them into the system and forwarding to IAS. I have rang my GP who is well aware of what is required of him for PIP, and also his colleague at the same surgery - neither have been requested to provide medical evidence, nor has our local hospital who have details of Xrays, etc. Rang IAS to ask why no medical evidence has been requested from GP`s or hospital to be told the assessor has everything they need to carry out the assessment.
I had attached lots of extra information for all the descriptors which effect my wife (Degenerative Osteoarthritis in hands, knees, fingers and lower back). I fail to see how they can give a proper assessment of my wife`s ability to carry out day to day activities without the vital medical evidence. Looks like this will be my first question on the assessment.