Corrected entry: For his wedding, Nazir is wearing a veil during the ceremony, and the bride is wearing red. These are characteristics from a Hindu wedding. The Khans are Muslims. (00:08:30)
Corrected entry: When the family goes to the phone box to ring Nazir, a coloured intercity train passes behind them. The film is set in 1971, but that type of train was not introduced until the mid 80s. Also, if you look closely at the house in the background, you can see the flashes from the electrified line, which again didn't happen until the mid 80s.
Correction: Actually, the InterCity trains (125/HST) were introduced in the early 70s, also, it may not have been the overhead lines but the actual rails of the train, and around that time, rails were electrified on many railways.
Correction: Correction here: British Rail used 25kV AC overhead electrification since the 1960s, particularly on the West Coast Main Line (which presumably is the location of this scene due to it being set and filmed in Manchester). The HST/InterCity 125 itself wasn't introduced till 1975, but the Mk2 coaches were introduced in 1964, so if this was set properly in time, the train would be fitting for that era, plus the power supply for the railway.
Correction: That's a Muslim tradition also.