i would say possible mention it to the staff, and say you have been doing a bit of research and was wondering if PDA could be what your daughter has. they should be fine with that and if any problems just say you were researching to aid in you being able to support your daughter adequately and so you could understand fully what she was going through.
I went to see my GP at the end of last year after my 6 year old daughters behaviour started to well, spiral out of control (was always on the verge of it!)
My google research has led me to think she could have PDA (ODD was previously suggested to me by a friend but PDA seems a better fit.
Do I mention what I think to CAMHS because I've heard two sides by other mums who've been through other dxs. Some say if you don't ask you don't get and others have said they don't like people stepping on their toes (sensitive egos etc). Along with the fact that my daughter said last night that the CAMHS woman was going to stab her when I mentioned it to her, although I tread VERY carefully when explaining anything to her is needed (she's a very anxious child and expects the worst and has a very violent imagination despite NO access to anything of that nature and also has been violent to me) so to be honest I was looking forward to finally getting somewhere but now the thought fills me with dread.