Considering that the subway outlets are mainly run by people of Asian or Muslim origin and Halal is usually suggested on their menu list, then perhaps those are the reasons why no pork and bacon are sold in some outlets?.
Not sure where it was, but the other day I noticed that one food outlet was stating what products were being cooked in the same cooking oil other were also being cooked in.
What I found very strange with Subway, is their 'free giveaway' promotions. Once had a newspaper voucher for an early breakfast sandwich, and the nearest Subway had sold out at 9AM, the exact same time that particular outlet opened. Must have been a very busy morning in the few seconds that they had unlocked their door?.