Damian is wearing a red, knit, collarless shirt and denim jacket at 14:24 on the DVD when speaking with St. Clare of Assisi in his cardboard hideaway. After the sports bag of money lands through his roof, he scrambles out in a yellow, knit, collared, school shirt and cloth or nylon jacket.
The railway line next to the new housing estate changes between electrified and non-electrified several times throughout the film as the overhead wires are not present in a number of scenes.
Nations transitioning to the euro were allowed to keep legacy currency in circulation as legal tender for two months - and, even after the official dates, they continued to be accepted for exchange by national central banks for varying periods - and indefinitely in some countries.
The UK never changed currency. It never adopted Euro.
Damien creates a bonfire of currency on a rail track. A train passes by and leaves the fire intact. We might expect the wind from the train to scatter the banknotes along the track.
Though the film is set around the Christmas holiday, several shots show verdant foliage only likely to be seen in summer. Director Danny Boyle explains the season difference at 30:44 in the DVD commentary and says he was told it looks more like Umbria (the Green Heart of Italy) than Manchester.
The film is set around Christmas in England. Yet shadows are relatively short indicating the time of shooting to be summer. The pupils in the playground are not wearing warm clothing, which they would if it were winter.
During the house-building sequence at the beginning of the film, the Moon is seen rising behind the house, but it moves upwards to the left. As the film is set in England (in the northern hemisphere), it should rise towards the right.