Hi David,
I’m afraid I am not enough of an expert to interpret spectra of CVs, beyond being able to tell the difference between the spectrum of a classical nova and one of a dwarf nova. This is a typical spectrum of a dwarf nova in outburst. In this case a large amplitude outburst of a star with no previous history of outbursts so a likely WZ Sge (UGWZ) type (I am reliant on Patrick Schmeer for this classification)
The source of the additional flux is impressively hot. The continuum fits to a ~35000K Planck curve, like an O star
Robin