In Year 5, Dumbledore’s Army, of Lego Harry Potter Years 5-7, how do you get into Puddifoots to collect the Slytherin piece of the Hogwarts Crest, assuming this is the correct location?
Your character doesn't actually go inside the tea shop. You need to use a character that has the Focus spell to take control of Madam Puddifoot (who has the ? above her head).
You will unlock the Focus Spell in year 5, after you have completed your second Occlumency lesson with Professor Snape. This lesson takes place after level 4 (Kreacher Discomforts) of year 5.
To learn the spell once and for all, you will need to relive Snape's memory, just as you did with Harry's in the level Focus!
When you Harry has learnt the spell, (or you have unlocked another character who has this ability), you need to stand outside the shop and cast Focus at Madam Puddifoot. You can then move her about so she can collect the Slytherin Crest piece that is inside her shop.