The "Assessment day" sounds like what our "low experience" pilots went through about 4 years ago as opposed to the more normal interview and sim ride that pilots with previous arline time do.
Which doesn't help nice24 best I can do is point this thread out to one of the ex-cadets and hope they reply to you.
oh and neil ment to say it was non-typed, low experience pilots who start on £29K, though that may have changed.