Mr Benns Any Era Clothes was the shop in the Time Hotel - Mr Benn was a BBC childrens show about a man who visits a costume shop then steps through a door to the costume-appropriate time and place.
Heh, I went and googled Mr Benn episode one and it features a Red Suit of Armour displayed in the shop window - the same suit of armour featured in the Dr Who episode! So direct reference confirmed