Ah, that explains it; I'll tell you why in a minute!
If either anti-D or anti-c is only detected by an enzyme technique, but not by a straightforward IAT (that is, with untreated red cells), then we should not report the quantification results. The same applies for other specificities, such as anti-K, anti-Jka, anti-whatever; if we only detect the antibody using enzyme-treated red cells, we should not report a titre, and yes, you are right, an antibody detected by "enzyme-only" techniques has never been implicated in a clinically significant case of HDFN.
Now then, why did I say "that explains it"? The answer is that quantification is no longer performed at Tooting, but is performed in Colindale. The first time a sample comes in during a pregnancy, which contains either an anti-D or an anti-c (or, God forbid, both!), Tooting does the serology, but a sample of the plasma is sent over to Colindale on the same day, and they (usually) perform the quantification on the same day, and enter it into the national computer. Once this is done, it is almost impossible (not quite, but almost impossible) to take it back off again, and involves paperwork equivalent to an old fashion telephone book for the Quality Department. After that, however, and as happened in your case, the quantification is not reported (and may not even be performed) unless the antibody has strengthened, and reacts by a "normal" IAT.
All that having been said, it still is wrong that "Enzyme Technique" has been used, rather than "Enzyme IAT" and, although I am no longer Head of the RCI Laboratory at Tooting (having taken over a national position as Reference Service Manager - Training), I am still based at Tooting, and will go to the Laboratory tomorrow and give them a good kicking!!!!!!!! All aspects of our reports should always be accurate!