I'd like to come back to the interview recently given by Professor Peter French on forensic acoustics. His speech style displays some features typical of colloquial English which, at times, make it difficult for EFL speakers to understand such an enunciation. I'm not saying, however, that Peter French's talk was difficult to understand; quite the contrary!
Fairly at the beginning of the interview - at about 1:13 minutes - he says: "[...] thirteen murders, which were carried out principally in West Yorkshire [...]." Listen to this part and concentrate on the words "which were":
Now look at the time-amplitude wave of these two words (it's a stereo recording):
I don't expect the weak-form of which = [ʍʧ] to have been recorded in CPD, EPD, LPD or ODP.