Bill Rigby

 was a window salesman.

One day, Bill appeared outside the TARDIS door — while it was in the time vortex — and knocked. The Second Doctor, Jamie McCrimmon and Zoe Heriot let him in. He gave them his sales pitch, urging them to consider his double-glazed windows. He even handed out leaflets featuring his products.

The Doctor bundled him out the door — back into the vortex — but Bill had left his umbrella behind. He climbed out of the TARDIS cupboard to continue his sales pitch. When he mentioned "your choice of view", the travellers became interested. He sold the Doctor a large, mock-Georgian bay window that had a view of the Doctor's childhood home. (PROSE: uPVC)