The same photo mug for weddings and the photographs from the day.
The same photo mug for a new arrival, a nursery or a first-year keepsake.
The same photo mug for anniversaries and milestone years together.
A mug clears most £10 and £15 office limits and is one of very few personalised gifts that does. An in-joke photo from the year lands better in that setting than anything bought off a shelf.
A photo of the grandchildren on the mug used every morning gets more looking-at than the same photo framed on a shelf. The magic mug version is the one children like giving.
Small enough to fit a stocking, personal enough not to read as filler. Pair with a set of six coasters from the same photograph if you want the gift to feel larger.
The end-of-term and end-of-year gift where something personal is welcome but anything expensive would be awkward. A photo the child took themselves solves it.