If HCW doesn't have any photos or videos of MM, why do you think it's so important to place a specific phone in CB's hands at 8pm on 3/5/07? What other data could be obtained from it which would prove CB killed Madeleine?
It would at least prove that CB was at PDL in that antena range on the exact time MM went missing ?
I think that someone like old CB "friends" provided BKA with it's "old" phone number.
Think about this, CB was in PT back in 2007 so BKA could NOT KNOW what vodafone number CB would have because it's not stated directly on the PJ files regarding MM case, meaning there is no link to phone number - name and BKA would need some sort of warrant to ask PT/PJ to do the phone search and by now many years did pass and the operators should only store records for 3 years.
BKA was "targeting" CB already at least since 2013 so from then on one can assume that they do have phone IMEI and with that link to all German cards that are placed on the phone. They would only know about PT cards if CB were to be using them in Germany in "roaming" mode and that is not likely because it would be expensive.
So assume that CB does have a +351 91 *advertiser censored* phone number, as soon as MM went missing and CB does return to Germany his phone will enter "roaming mode" as soon as he reach Spain, so it's likely that he placed that +351 91 *advertiser censored* fone card in the garbage bin and aquire a german pre-paid card or any other phone plan when arriving to Germany.
By that point even if BKA does have the phone number and can match with the phone unique IMEI they can reverse the search and find ALL CARDS/NUMBERS that were associated with that IMEI as well BUT ONLY IN GERMANY. They couldn't for example to know that a PT card was used on PT on that same IMEI unless they do have a court order and provide that to PT and ask them to tell them all numbers from all operators that were used on that phone IMEI.
Since HCW ONLY stated that MM was killed by CB and he does have some "secret evidences" and he is asking for more info about the phone number i would say it's not likely at all that BKA did request PT/PJ info about those numbers. I would say that someone like old CB friend did gave/provide BKA with the number that CB did use in Portugal. That is was more likely and becauase they were friends the old CB friend would have the number.
Now BKA do compare that number with the PJ excell sheet for MM case and they figure out that not only CB/the phone number that they have for CB was on PDL near the place where MM went missing but only he did get a 30min call like we all know.
IF BKA can place that phone on the hands of CB at that time it will prove that CB was on the crime scene FOR SURE so he could possible had snatched MM.
By itself it will not be enough but it's a start.
Scottish blood ! 
